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(981 - 1,000 of 4,268)
Pages
- Title
- Design for the proposed outer harbor of the city of Chicago
- Creator
- Ferrenz, Tirrell J
- Date
- 2009, 1911
- Publisher
- Armour Institute of Technology
- Description
-
http://www.archive.org/details/designforpropose00ferr
Thesis (B.S.)--Armour Institute of Technology, 1911 Bibliography: leaf iii B.S. in Civil...
Show morehttp://www.archive.org/details/designforpropose00ferr
Thesis (B.S.)--Armour Institute of Technology, 1911 Bibliography: leaf iii B.S. in Civil Engineering, 1911
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- Title
- Design and estimate of approximate cost of a sanitary sewer system for the village of Barrington, Cook and Lake counties, Illinois
- Creator
- Jucker, J., Jr, Trinkaus, G. J
- Date
- 2009, 1915
- Publisher
- Armour Institute of Technology
- Description
-
http://www.archive.org/details/designestimateof00juck
Thesis (B.S.)--Armour Institute of Technology; Includes folded leaves in back pocket;...
Show morehttp://www.archive.org/details/designestimateof00juck
Thesis (B.S.)--Armour Institute of Technology; Includes folded leaves in back pocket; Bibliography: leaf 1
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- Title
- The design and estimated weight of a cantilever bridge
- Creator
- Zeman, Leonard, Siedenstrang, Otto
- Date
- 2009, 1914
- Publisher
- Armour Institute of Technology
- Description
-
http://www.archive.org/details/designestimatedw00zema
Thesis (B.S.)--Armour Institute of Technology; Bibliography: leaves 55-60
- Title
- Design and experimental study of a capillary electrometer
- Creator
- Kahn, Lamos, Ostergren, Harry
- Date
- 2009, 1909
- Publisher
- Armour Institute of Technology
- Description
-
http://www.archive.org/details/designexperiment00kahn
Thesis (B.S.)--Armour Institute of Technology
- Title
- Design and estimate of the improvement of the fifth street road through the Little Vermillion Valley at La Salle, Illinois
- Creator
- Eliel, R. G, Clarkson, W. Jr., Eckert, J. M
- Date
- 2009, 1910
- Publisher
- Armour Institute of Technology
- Description
-
http://www.archive.org/details/designestimateof00elie
Thesis (B.S.)--Armour Institute of Technology, 1910 B.S. in Civil Engineering, 1910
- Title
- Design and estimate of cost of steel superstructure and concrete substructure of a river crossing for highway traffic
- Creator
- Holmboe, J. A.
- Date
- 2009, 1914
- Publisher
- Armour Institute of Technology
- Description
-
http://www.archive.org/details/designestimateof00holm
Thesis (B.S.)--Armour Institute of Technology; Bibliography: leaf 58
- Title
- A design for the Hocking Valley power project
- Creator
- Burris, Edward, Deering, John J., Mammes, Harry A, Sullivan, Thomas F
- Date
- 2009, 1915
- Publisher
- Armour Institute of Technology
- Description
-
http://www.archive.org/details/designforhocking00burr
Thesis (B.S.)--Armour Institute of Technology;Includes folded leaves in back pocket
- Title
- PHOTOCATHODE TUNABILITY: THE PHOTOEMISSIVE PROPERTIES OF ULTRA-THIN MULTILAYERED MgO/Ag/MgO FILMS SYNTHESIZED BY PULSED LASER DEPOSITION
- Creator
- Velazquez, Daniel Gomez
- Date
- 2015, 2015-05
- Description
-
Much of the early development of photocathode materials was aimed at the growth of photoemissive thin films with low work function, and high...
Show moreMuch of the early development of photocathode materials was aimed at the growth of photoemissive thin films with low work function, and high quantum efficiency (QE). It has been shown, both theoretically and experimentally, that metal-insulator junctions can lead to the modification of the work function and QE for coverages of a few monolayers of metal oxides on metallic substrates. However, the production of electron beams suitable for new photoinjector technologies in many instances requires low emittance beams from the cathode itself. Often the cathode intrinsic emittance plays an important role in new e-gun designs. A demonstration of the ability to control photoemissive properties by engineering the band structure of a photocathode could provide a pathway to meet the demands of new photoinjector technologies. Nemeth et al. [Phys. Rev. Lett. 104, 046801 (2010)] used density functional theory (DFT) to model the properties of a multilayered structure of MgO/Ag(001)/MgO with 4 monolayers of Ag(001) flanked by n monolayers (ML) of MgO. Their model indicated that it is possible to reduce the emittance of a photoemitted electron beam when the thickness n of the MgO layers is 2 or 3 monolayers because the surface band structure exhibits a narrowing of the density of occupied states in momentum near the Γ-point neighboring the Fermi Level. The theoretical prediction concerning the emission properties of these multilayers structures was tested by fabricating them, and then characterizing their emission properties. Synthesis of multilayered MgO/Ag/MgO films was performed using a custom-built pulsed laser deposition (PLD) system. In-situ growth monitoring was carried out by Reflection High-Energy Electron Diffraction (RHEED). Ex-situ techniques such as Scanning Tunneling Microscopy (STM), Scanning Electron Microscopy/Energy Dispersive Spectroscopy (EDS) and Photoelectron Spectroscopy (PES) were used to show the formation of the crystalline and chemical structure of the multilayered films. A Kelvin Probe/photocurrent-detector system, custom-built for this research, was used to measure the work function and QE of the samples. Angle Resolved Photoelectron Spectroscopy was used to measure the angular photoelectron yield. Simultaneous reduction of work function and increase of QE was observed for (001) oriented multilayers of various thicknesses with respect to that of a bare Ag/MgO(001) surface. Work function measurements of multilayers of various thicknesses in the (111) orientation also registered a monotonic reduction with respect to that of a bare Ag/Si(111) surface. Angular emission was compared for a MgO/Ag/MgO multilayer (thicknesses of 3 ML/4 ML/3 ML) sample and Ag/MgO(001). Emission analysis of the angle-resolved photoelectron spectra shows a net change in the angular emission with high kinetic energy electron density shifted toward surface-normal emission. Experimental results were consistent with theoretical predictions, which open the promising possibility of customizing emission properties by direct manipulation of the surface band structure of the emitter.
Ph.D. in Physics, May 2015
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- Title
- PREDICTING COMMENT QUALITY ON NEWS WEBSITES: LINGUISTIC INDICATORS AND VIEWS FROM JOURNALISM PROFESSIONALS
- Creator
- Scott, Edward Blake
- Date
- 2014, 2014-07
- Description
-
As the web has become more interactive in recent years, with website users having the ability to generate their own content, there has been...
Show moreAs the web has become more interactive in recent years, with website users having the ability to generate their own content, there has been increased tension between the content generated by users and the content generated by “professionals,” especially professional journalists and publishers. Many journalism professionals see the value of allowing users to comment on their work; for example, an interactive site that allows user commenting may increase users’ loyalty to the site, meaning they will return often, generate page views, and increase advertising revenue. Users can also serve to further explore an issue discussed in an article by broadening the discussion to include the viewpoints of those who aren’t professional journalists. However, publishers of news site comments have noted many problems with introducing user-generated content (UGC) to their sites, including the fact that users sometimes post inflammatory, insensitive, or lowquality comments that do not serve to improve the experience of the average reader. The problems caused by these kinds of comments have increased the amount of time and money required to moderate the comments section. Beyond inflammatory comments, however, is the problem of highlighting very good or high-quality comments. What is the degree to which those high-quality comments can be discovered through an automated process? This dissertation sought to test the extent to which comments to news sites can be automatically evaluated for quality by using a text-analysis system. Journalists were interviewed to get their views on user comments in general and comment quality in particular. The data from these interviews was used to generate hypotheses about which linguistic metrics provided by Coh-Metrix, a web-based text-analysis system, might be xiii most indicative of comment quality as described by journalists. Finally, a content analysis and close reading of a sample of news site comments was conducted in order to describe news site comments as a writing genre. Results from the interviews indicated that comment length, comment syntax, comment cohesion, comment narrativity, and comment individuality were all indicative of comment quality. However, statistical analyses on a sample of 246 comments failed to produce significant results for linguistic metrics hypothesized to be indicative of quality. Alternatively, an “positive engagement score” scale was created and used to identify how “engaging” comments were; this scale showed to have a significant, though minor, positive relationship with the number of recommendations a comment received from readers. Finally, the genre analysis of the sample of news site comments revealed that comments in the sample share a communicative purpose of providing additional content related to the article under discussion, providing a practical value for journalists and other professionals by offering tips and fact-checking functions, and providing a space where readers can debate the article in question and begin to develop a sense of community.
Ph.D. in Technical Communication, July 2014
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- Title
- OPTIMAL ROUTING ALGORITHMS IN ENERGY-HARVESTING WIRELESS SENSOR NETWORKS
- Creator
- Martinez, Gina
- Date
- 2014, 2014-12
- Description
-
Harnessing energy from environmental sources such as solar and wind is an attractive solution to the critical energy limitation problem in...
Show moreHarnessing energy from environmental sources such as solar and wind is an attractive solution to the critical energy limitation problem in wireless sensor networks. Energy harvesting can potentially provide the network with perpetual and sustainable operation, or it can prolong network lifetime even for high consumption applications so as to justify the high cost of deployment. However, in order to efficiently utilize harvested energy, the energy source dynamics need to be incorporated into the network design. One way to do so is to make the network layer routing algorithm energy-harvest-aware. One common property of environmental energy sources is that they are generally only intermittently available. To address this, a storage unit such as a rechargeable battery can be introduced into the system. However, this is only a partial solution due to finite buffer storage capacities that cause harvested energy to be wasted when full. In this work, we aim to maximize the network lifetime by optimizing the energy availability and consumption alignment. To realize this objective, we first show that the minimization of energy wastage is a necessary condition to the maximization of available network energy. We then propose an on-demand routing algorithm that maximizes the total residual network energy by minimizing the energy consumption and wastage. Next, we illustrate the tradeoff between the two objectives of maximizing the total network energy and maximizing the minimum network energy in prolonging network lifetime. Then, we propose a linear-programming routing solution that maximizes a utility objective function based on this tradeoff. Although these routing approaches are shown to achieve high energy utilization, they are still based on deterministic harvest and consumption models. In the last part of this work, we propose a routing algorithm by applying the Semi-Markov Decision Process. Using this method, we are able to incorporate a comprehensive consideration of stochastic solar availability and traffic models, heterogeneous network properties such as non-uniform energy buffer capacities and consumption rates, and the optimization of an analytical formulation for network lifetime.
Ph.D. in Electrical and Computer Engineering, December 2014
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- Title
- DESIGN AND OPTIMIZATION OF CONFIGURABLE PASSIVE COMPONENTS FOR CMOS MILLIMETER-WAVE INTEGRATED CIRCUITS
- Creator
- Liu, Gui
- Date
- 2011-05-10, 2011-05
- Description
-
With the rapid growth of wireless communications, there is an increasing demand for low cost, low power consumption, high data rates and high...
Show moreWith the rapid growth of wireless communications, there is an increasing demand for low cost, low power consumption, high data rates and high density integrated circuits. The continuous scaling of CMOS technologies promises to achieve higher frequencies of operation in the millimeter-wave (mm-wave) frequency regime. To enable lager bandwidth for higher data rates wireless applications, many efforts have been focused on the design of mm-wave CMOS integrated circuits. The emerging mm-wave wireless commercial applications such as Wireless Hi-definition Video (60 GHz), automotive radar (77 GHz) and mm-wave imaging system (94 GHz) have brought new challenges in devices technology and systems. There is an ever increasing demand for multi-band and multi-mode integrated wireless communication systems which have the advantages of power and area savings. Therefore, flexible and configurable mm-wave on-chip components and circuits are needed to accommodate a wide variety of wireless communication standards. On the other hand, the first silicon success of the challenging mm-wave integrated circuits requires superior and robust design capabilities in cutting-edge technologies. To satisfy customers by providing them with the fastest time-to-market and the lowest total cost, the configurable multiband mm-wave solution is preferred. Design of on-chip passive components operating at millimeter wave frequencies presents several challenges due to the ohmic loss, parasitic inductance and capacitance. Therefore, it requires both an accurate model and electromagnetic (EM) simulation tools to characterize the passive components. The other challenge of design of mm-wave on-chip passives is process variations which can have a significant effect on the robustness of the passive components and circuits. Methodology to compensate and adjust for process variations is needed. Passives that can be configured after fabrication would be an attractive way to obtain accurate parameters and overcome effects of process variations. The configurable Multilayer Coplanar Waveguide (MCPW) based transmission lines offer convenient method to alleviate the problem of process variations and obtain accurate inductor values. This dissertation focuses on the design of mm-wave passive components and their applications. Model, EM simulation, and optimization of several novel MCPW-based configurable inductors are presented. A 77-GHz voltage controlled oscillator (VCO) and a 77-GHz receiver employing the configurable inductors have been realized. The 77-GHz VCO with MCPW-based configurable inductor exhibits low phase noise and wide frequency tuning range. The 77-GHz receiver achieves low power and state-of-the-art performance. The successful implementations of several individual configurable passive components, a 77-GHz VCO, and a 77-GHz receiver demonstrate the feasibility to achieve good performance and robust design with configurable passive components.
Ph.D. in Electrical Engineering, May 2011
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- Title
- A LONGITUDINAL STUDY OF POSTTRAUMATIC SYMPTOMS AND POSTTRAUMATIC GROWTH IN ONCOLOGY PATIENTS
- Creator
- Thilges, Sarah R
- Date
- 2013, 2013-07
- Description
-
Cancer has been observed and studied within the development of both posttraumatic stress disorder (PTSD) and posttraumatic growth (PTG)...
Show moreCancer has been observed and studied within the development of both posttraumatic stress disorder (PTSD) and posttraumatic growth (PTG) although reported prevalence rates of PTSD vary greatly and PTG rates are even less established. The current longitudinal study seeks to elucidate which factors are related to endorsing PTSD and PTG symptoms among oncology patients. One hundred and twenty-five patients completed measures at Time 1 assessing rates and predictors of PTSD and within the same sample, 75 patients completed measures assessing rates and predictors of PTG four years later (Time 2). A model containing utilization of venting along with greater trauma impact ratings significantly predicted PTSD symptoms at Time 1, although none of the variables were independent significant predictors. At Time 2, results indicate using spirituality as support and greater obsessive and depressive symptoms at T1 predicted PTG although only spirituality was a significant independent predictors. Results have implications for clinical and research work to address and monitor potential risk factors for distress and strengths which may promote PTG.
PH.D in Psychology, July 2013
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- Title
- ANTI-STIGMA PROGRAMS: STIGMA IN CAMPUS POlICE OFFICERS
- Creator
- Rafacz, Jennifer D.
- Date
- 2012-07-19, 2012-07
- Description
-
It has been proposed that the most effective way to combat mental illness stigma is to focus on power groups who have a direct impact on the...
Show moreIt has been proposed that the most effective way to combat mental illness stigma is to focus on power groups who have a direct impact on the lives of persons with serious mental illness. With the increase of violence and need for mental health services on college campuses, campus police officers are seen as an important power group for persons with serious mental illness. This study assessed the effects of online contact versus online education anti-stigma programs on campus police officers attitudes toward persons with serious mental illness. The study also considered moderators of contact specifically level of familiarity, state empathy, and trait empathy. It was found that the online program was not effective in changing attitudes. The research also suggested that the attitudes of the campus police officers were generally non-stigmatizing other than the endorsement of fear/danger. Both state and trait empathy were found to be moderators helping behaviors and social distance. Level of familiarity was not found to be a moderator of social distance. The findings suggest that future research and stigma work with campus police officers should focus on in vivo behaviorally driven interventions such as crisis intervention training with a focus on danger/fear.
Ph.D. in Psychology, July 2012
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- Title
- A COMPARISON OF META-ANALYTIC PROCEDURES WHEN PRE- AND POSTTEST VARIANCES ARE HETEROGENEOUS
- Creator
- Collins, Michael W.
- Date
- 2011-11, 2011-12
- Description
-
Meta-analysis is a statistical method for aggregating summary results from archival research. Traditional meta-analysis procedures that...
Show moreMeta-analysis is a statistical method for aggregating summary results from archival research. Traditional meta-analysis procedures that involve repeated measures assume homogeneous variances in pretests and posttests, an assumption which is often violated in training evaluation contexts due to variance inflation in posttests. A new meta-analytic procedure that allows for heterogeneous variance in pretests and posttests was tested in the context of leadership and managerial training programs. Application of the new method revealed greater sampling variance and less between-study variance than traditional meta-analysis with little effect on estimation of the mean effect size. However, the procedure screened out a large number of studies due to the intensive data requirements, which limited the number of usable studies for the meta-analysis.
Ph.D. in Psychology, December 2011
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- Title
- HARDWARE-EFFICIENT VLSI IMPLEMENTATION FOR PARALLEL LINEAR-PHASE DIGITAL FIR FILTER
- Creator
- Tsao, Yu-chi
- Date
- 2011-11, 2011-12
- Description
-
Along with the explosive growth of multimedia applications, the number of gates required and the area consumed in very-large-scale integration...
Show moreAlong with the explosive growth of multimedia applications, the number of gates required and the area consumed in very-large-scale integration (VLSI) for digital signal processing (DSP) is getting higher and higher. Therefore, the demand for low-complexity and low-cost VLSI architectures for DSP, which occupies area as small as possible while remaining high performance, is imperatively needed. Finite impulse response (FIR) digital filter is one of the most widely used fundamental devices performed in DSP systems, ranging from wireless communications to video and image processing. Furthermore, when narrow transition band characteristics are required, the much higher order in the FIR filter is unavoidable. For instance, a 576-tap digital filter is used in video ghost canceller for broadcast television, which reduces the effect of multi-path signal echoes. On the other hand, parallel and pipelining processing are two techniques used in DSP applications, which both can be exploited to reduce the power consumption. Parallel processing applied on FIR digital filter can either increase the throughputs for high-speed processing or reduce the power consumption of the original sequential filter by lower supply voltage. Hence, there have been several architectures for parallel FIR digital filter proposed in the past. However, for symmetric convolutions, linear phase digital FIR filter, these proposed architectures are not beneficial in terms of hardware consumption. In this dissertation, new parallel FIR digital filter architectures which can save significant hardware cost by exploiting the inherent nature of symmetric convolutions, namely linear phase digital FIR filter, are presented. This dissertation is mainly divided into four chapters. In chapter one, some prerequisites as the background related to parallel finite impulse response (FIR) digital xi filter design and implementation are introduced, including conventional parallel FIR digital filter architectures, parallel FIR digital filter structures based on fast FIR algorithm (FFA), previously proposed architectures for parallel FIR filter, maximum absolute difference (MAD) quantization algorithm, canonic signed digit (CSD) representation and CSD multipliers for constant multiplications, are introduced and reviewed. In chapter two, the proposed parallel FIR digital filter structures for symmetric convolutions of even length are presented, in which the complexity and experimental results are analyzed and compared with FFA-based parallel FIR digital filter and other previously proposed structures. In chapter three, the proposed parallel FIR digital filter architectures for symmetric convolutions of odd length are presented, in which the complexity and the benefit of structures are analyzed and compared with FFA-based parallel FIR digital filter and other previously proposed structures The last chapter, chapter four, gives the summary and the conclusion of the proposed parallel linear-phase FIR digital filter.
Ph.D. in Electrical Engineering, December 2011
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- Title
- PARTICLE FILTERING ESTIMATION APPROACH IN ADVANCED DIGITAL COMMUNICATION SYSTEMS
- Creator
- Huang, Lun
- Date
- 2013, 2013-05
- Description
-
The ever-increasing volume of users and the demand for more communication services bring about many advanced modulation and demodulation...
Show moreThe ever-increasing volume of users and the demand for more communication services bring about many advanced modulation and demodulation technologies which are developed to increase the spectrum efficiency and cope with challenging transmission conditions in digital communications. However, it is difficult to improve the performance of those traditional modulation and demodulation approaches without increasing transmit power and lowering spectrum efficiency. This thesis studies the application of powerful Particle Filtering methods to the problems associated with the interference cancellation, equalization, demodulation, and decoding of the signals over communication channel. In this thesis, theoretic models of using particle filtering approaches in digital communications are investigated, and several specific algorithms and schemes are considered as applications of the theoretic models. First, the application of particle filtering in delayed decision feed-back sequence estimation equalization is addressed. The particle filtering approach is then introduced to an efficient particle filtering receiver for inter-carrier interference cancellation and demodulation of M-ary modulated signals in OFDM/OFDMA system under time-variant Rayleigh fading channels. Subsequently, an efficient sequential Monte Carlo (SMC) demodulation approach for Polynomial Phase Modulation (PPM) is discussed. The interference cancellation and demodulation algorithm for MIMO-PPM scenario is then derived. The analysis of performance and computational complexity for SMC particle filtering approach is also provided. Comprehensive simulation results confirm that the proposed sequential Monte Carlo particle filtering approaches have better performance than the conventional methods.
PH.D in Electrical Engineering, May 2013
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- Title
- EXPANDING FAITH-BASED ORGANIZATIONS’ ADAPTATION OF STREAMING TECHNOLOGY
- Creator
- Johnson Winston, Patty D.
- Date
- 2011-07-18, 2011-05
- Description
-
In the field of technical communication there exist few studies that specifically address faith-based organizations’ use of communication...
Show moreIn the field of technical communication there exist few studies that specifically address faith-based organizations’ use of communication technology. The purpose of this dissertation was to show how these organizations can expand their use of streaming technology by using principles and practices that are common in technical communication. This was addressed in three phases. First, a review of the relationship between religion and media was conducted. It revealed that faith-based organizations are early adaptors of communication technology. Communication technology is used to widely broadcast their organizational missions, tenets and goals. By accomplishing these tasks, faith-based organizations seek to educate and reinforce cultural norms, images, and belief systems among their adherents and attract new members. Second, an examination of theories and instructional practices found in technical communication was conducted. It was determined that adapting a learning-centered approach to instruction can be applied to a distance education model for faith-based education. Third, faith-based websites were analyzed to determine types and current uses of communication technology. It was established that most of the organizations that offer educational courses do not conduct them online, even if they already use streaming media for other purposes. The findings suggest that faith-based organizations’ use of streaming technology for educational purposes is an area of inquiry that should be further explored by technical communicators. Technical communication provides a rich array of disciplines from which to draw, such as Instructional Design, Information Architecture, and Usability.
Ph.D. in Technical Communication, May 2011
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- Title
- TECHNOLOGY INTEGRATION IN SCIENCE EDUCATION: A STUDY OF HOW TEACHERS USE MODERN LEARNING TECHNOLOGIES IN BIOLOGY CLASSROOMS
- Creator
- Gnanakkan, Dionysius Joseph
- Date
- 2017, 2017-07
- Description
-
This multiple case-study investigated how high school biology teachers used modern learning technologies (probes, interactive simulations and...
Show moreThis multiple case-study investigated how high school biology teachers used modern learning technologies (probes, interactive simulations and animations, animated videos) in their classrooms and why they used the learning technologies. Another objective of the study was to assess whether the use of learning technologies alleviated misconceptions in Biology documented by American Association for the Advancement of Science. The sample consisted of eight teachers: four rural public school teachers, two public selective enrollment school teachers, and two private school teachers. Each teacher was followed for two Units of instruction. Data collected included classroom observations, field notes, student assignments and tests, teacher interviews, and pre-and post-misconception assessments. Paired t-tests were done to analyze the pre-post test data at a significance level of 0.05 and the qualitative data was analyzed using the constant comparative method. Each case study was characterized and then a cross-case analyses was done to find common themes across the different cases. Teachers were found to use the learning technologies as a tool to supplement instruction to visualize abstract processes, collect data, and explore abstract concepts and processes. Teachers were found to situate learning, use scaffolding and questioning and make students work in collaborative groups. The genetics, photosynthesis, and evolution misconceptions were better alleviated than cellular respiration. Student work that was collected demonstrated a superficial understanding of the concepts under discussion even when they had misconceptions. The teachers used the learning technologies in their classrooms for a variety of reasons: visual illustrations, time-saving measure to collect data, best way to collect data, engaging and fun for students and the interactive nature of the visualization tools and models. The study’s findings had many implications for research, professional development, teacher education, teaching practice, administrators, and learning technology developers. More detailed research within similar school settings (public, charter, and private) is needed to verify the common findings across the different cases in this study. An implication is that learning technology integration could be modeled with instructional scaffolds and questioning and incorporating higher order thinking tasks. Learning technology developers should consider the collaborative learning groups while developing these technologies.
Ph.D. in Science Education, July 2017
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- Title
- COORDINATED DRIVING IN CONNECTED AND AUTONOMOUS VEHICLE SYSTEM -- OPTIMAL ADVANCE LANE CHANGE ZONES AND COORDINATED PLATOON CAR FOLLOWING CONTROL
- Creator
- Gong, Siyuan
- Date
- 2017, 2017-07
- Description
-
The connected and autonomous vehicle (CAV) system enables countless innovative coordinated driving approaches, such as coordinated lane change...
Show moreThe connected and autonomous vehicle (CAV) system enables countless innovative coordinated driving approaches, such as coordinated lane change and car-following in microscopic CAV control, and coordinated rounding and parking in macroscopic traffic flow guidance, which will improve the performance of our transportation system by enhancing traffic mobility, providing safe driving environment and reducing fuel consumption. Since the lane change and car-following behavior are indicated as crucial factors of traffic safety and efficiency, this dissertation focuses on developing the coordinated driving schemes in microscopic control and operation of lane change and car-following maneuvers. In particular, I develop an lane change zone optimization strategy and the coordinated platoon car-following control for a pure CAV platoon and a mixed platoon (i.e. mixed with human-drive vehicles and CAVs) respectively. This dissertation first explore the management strategy of the mandatory lane change near a two-lane highway off-ramp by optimizing the location of advance warning. The proposed approach considers that the area downstream of the advance warning includes two zones: the green and yellow zones corresponding to their respective most like lane change maneuvers. An optimization model is proposed to search for the optimal green and yellow zones. Traffic flow theory such as Greenshield model and shock wave analysis are used to analyze the impacts of the S-MLC and D-MLC maneuvers on the traffic delay. Numerical experiments indicate that the proposed optimization model can identify the optimal location to set the advance MLC warning nearby an off-ramp so that the traffic delay resulting from lane change maneuvers is minimized, and the corresponding capacity drop and traffic oscillation can be efficiently mitigated. Then, this research develops a novel car-following control scheme for a platoon of connected and autonomous vehicles on a straight highway. The platoon is modeled as an interconnected multi-agent dynamical system subject to physical and safety constraints. A constrained optimization based control scheme is proposed to ensure an entire platoon’s transient traffic smoothness and asymptotic dynamic performance. This dissertation develops dual based distributed algorithms to compute optimal solutions with proven convergence. Furthermore, the asymptotic stability of the unconstrained linear closed-loop system is established. These stability analysis results provide a principle to select penalty weights in the underlying optimization problem to achieve the desired closed-loop performance for both the transient and the asymptotic dynamics. By the motivation that CAVs and human-drive vehicles will co-exist on the road for a long period in the near future, the third part of this dissertation extends the pure CAV coordinated platooning control to the mixed flow environment. By integrating the Newell car-following model, a real-time curve matching algorithm is implemented to calibrate the ca-following model and anticipate the movement of human-drive vehicle by the real-time trajectory data. The constrained MPC are developed for each CAV platoon, considering their movement interaction through the human-drive vehicle platoon. Furthermore, this study provide a modified dual based distributed algorithm to improve convergence speed of the primal problem for the dual based distributed algorithm in Chapter 4. Several requirements of the penalty weights selection are provided by stability analysis under the unconstrained conditions. The numerical experiments based on field data will be conducted to illustrate the effectiveness and efficiency of the proposed the solution approach and the platoon control schemes.
Ph.D. in Civil Engineering, July 2017
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- Title
- INTEGRATED PLANNING OF BEV PUBLIC FAST-CHARGING STATIONS
- Creator
- Gong, Lin
- Date
- 2015, 2015-12
- Description
-
This thesis proposes a multi-layer strategy and an abstract map method to achieve an integrated planning of public fast-charging stations to...
Show moreThis thesis proposes a multi-layer strategy and an abstract map method to achieve an integrated planning of public fast-charging stations to charge certain number of lightduty battery electric vehicles in a given geographic region under its existing environment, aiming to improve application of electric vehicle in the studied region and finally enhance social welfare in a long term by optimally locating public fast-charging stations and assigning their installed capacities to maximize the possibility of effectively charging battery electric vehicles, as well as to minimize the infrastructure cost and mitigate possible negative impacts on the transportation system and the electric power system. In the first layer of this multi-layer strategy, the conditions of the transportation system are considered, analyzed and mathematically modeled, while in the second layer, based on the former layer, the conditions of the electric power system are incorporated. Then in the third layer, an integrated planning of public fast-charging stations is achieved by combining both the transportation system's and the electric power system's conditions. From the first to the last layer, a case is studied in each layer to test the idea, method and also the mathematical model which is built by the MILP method. These works are based on an abstract road network map which is rooted in the actual map of a representative geographic region. After the optimal results based on the abstract map are obtained, they will be mapped back to the actual map of the representative geographic region. Therefore, the ideas, methods and solutions studied in this thesis aiming to achieve an integrated planning of public fast-charging stations to charge battery electric vehicles are able to be applied in practice.
M.S. in Electrical Engineering, December 2015
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