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Automated Fault Detection, Diagnostics, Impact Evaluation, And Service Decision-Making For Direct Expansion Air Conditioners, Andrew L. Hjortland May 2018

Automated Fault Detection, Diagnostics, Impact Evaluation, And Service Decision-Making For Direct Expansion Air Conditioners, Andrew L. Hjortland

Open Access Dissertations

This work describes approaches for automatically detecting, diagnosis, and evaluating the impacts of common faults in unitary rooftop air conditioning equipment. A semi-empirical component-based modeling approach using virtual sensors has been implemented using low-cost microcontrollers and tested on fixed-speed and variable-speed equipment using laboratory psychrometric test chambers. A previously developed virtual refrigerant charge sensor was applied to a fixed-speed rooftop unit with combinations of condenser types and expansion valve types and resulted in average prediction errors less than 10%. In addition, a methodology was developed that can be used to tune the empirical parameters of the model using data collected …

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How Heat Affects Human Hair: Thermal Characterization And Predictive Modeling Of Flat Ironing Effects, Jaesik Hahn May 2018

How Heat Affects Human Hair: Thermal Characterization And Predictive Modeling Of Flat Ironing Effects, Jaesik Hahn

Open Access Dissertations

Many people with curly hair experience heat damage – loss of curls and structural degradation of hair – after repetitive use of flat irons. While an array of relevant studies provide insight into thermochemical processes behind the phenomenon, practical tools for flat iron users are unavailable. As a result, people shun heat for fear of unpredictable amount of heat damage while adopting other laborious methods to satisfy a persevering need for temporary hair straightening. Thus three overarching research projects emerge to address the problem. In Part 1, I develop an empirical approach to mathematically correlate four flat ironing parameters (a …

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Techniques For Reconstructing A Riemannian Metric Via The Boundary Control Method, Paul A. Kepley May 2018

Techniques For Reconstructing A Riemannian Metric Via The Boundary Control Method, Paul A. Kepley

Open Access Dissertations

In this dissertation, we consider some new techniques related to the solution of the inverse boundary value problem for the wave equation with partial boundary data. Most results are formulated in a geometric setting, where waves propagate in the interior of a smooth manifold with smooth boundary M, and the wave speed is modelled by an unknown Riemannian metric g. For data, we focus mostly on using the Neumann-to-Dirichlet (N-to-D) map with sources and receivers restricted to a measurement set Γ ⊂ ∂M. The goal of the inverse problem, in this setting, is to use these wave boundary measurements to …

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Ultra Purification Of Gallium By Zone Refining, Daniel Kim May 2018

Ultra Purification Of Gallium By Zone Refining, Daniel Kim

Open Access Dissertations

High electron mobility is essential to improve two-dimensional electron gas (2DEG) quality in MBE grown AlGaAs/GaAs heterostructures. Recently, gallium purity was identified as limit to electron mobility in such structures. A laboratory horizontal zone refiner was constructed and procedures such as cleaning operation and handling/extracting samples were developed to suit needs for producing ultra-high purity gallium. One major problem is that most of the impurities are already below detection limit of current measurement techniques for starting high purity gallium. The 8N gallium (99.999999%, 10 ppb nominal purity) is the most pure commercially available gallium and measuring the purity becomes difficult …

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Large Scale Constrained Trajectory Optimization Using Indirect Methods, Thomas Antony May 2018

Large Scale Constrained Trajectory Optimization Using Indirect Methods, Thomas Antony

Open Access Dissertations

State-of-the-art direct and indirect methods face significant challenges when solving large scale constrained trajectory optimization problems. Two main challenges when using indirect methods to solve such problems are difficulties in handling path inequality constraints, and the exponential increase in computation time as the number of states and constraints in problem increases. The latter challenge affects both direct and indirect methods. A methodology called the Integrated Control Regularization Method (ICRM) is developed for incorporating path constraints into optimal control problems when using indirect methods. ICRM removes the need for multiple constrained and unconstrained arcs and converts constrained optimal control problems into …

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Evaluation Of Reactivity Feedbacks Due To Core Deformation In Fast Reactors, Tian Jing May 2018

Evaluation Of Reactivity Feedbacks Due To Core Deformation In Fast Reactors, Tian Jing

Open Access Dissertations

In order to meet the worldwide demands on sustainable energy, new generation of nuclear reactor systems has been proposed to continue the benefit of nuclear power for electricity production. Sodium-cooled fast reactor (SFR) is one of the most promising candidate among those reactor concepts for both energy production and minimizing radioactive nuclear waste and features inherent safety potential. To ensure inherent safety characteristics of SFR, accurate evaluation of reactivity feedbacks is essential. However, accurate evaluation of the negative reactivity induced by the core radial expansion and assembly bowing remains challenging. SFR has a relatively large coolant temperature rise, and thus …

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Welfare Impcats Of Optimal Virtual Bidding In A Multi-Settlement Electricity Market With Transmission Line Congestion, Hyungkwan Kim May 2018

Welfare Impcats Of Optimal Virtual Bidding In A Multi-Settlement Electricity Market With Transmission Line Congestion, Hyungkwan Kim

Open Access Dissertations

With a goal of improving the performance of wholesale electricity markets, virtual financial products have been introduced. Virtual bids are purely financial instruments that may be used to speculate on the differences between prices in the forward and spot markets in a two-settlement electricity market. While there is evidence that price convergence across these markets can be induced by virtual bidding, other research has shown that the impacts on the welfare of market participants are less clear. The problem is that, while virtual bidding may narrow the price gap, if it does so by inflating the prices, then electricity consumers …

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The Effects Of A Career Development Intervention On The Career Aspirations Of Middle School Students, William E. Kovach May 2018

The Effects Of A Career Development Intervention On The Career Aspirations Of Middle School Students, William E. Kovach

Open Access Dissertations

The purpose of the study was to identify and evaluate the effectiveness of a career development program at the middle school level. The intent was to provide middle school students with the necessary formalized support to assist them to develop self-awareness and self-efficacy, understand why they are in school, connect long-term goals with the steps needed to achieve those goals, and receive support from the teacher/advisor, counselors, and business community throughout the process. Further, through the tenets of Social Cognitive Career Theory and values-affirmation intervention, the purpose was to implement an introspective opportunity for students to reflect on their career …

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Stereotype Threat, Perfectionism, And Women's Career Outcomes, Chaihua Lin May 2018

Stereotype Threat, Perfectionism, And Women's Career Outcomes, Chaihua Lin

Open Access Dissertations

The underrepresentation of women in science, technology, engineering, and mathematics (STEM) calls for efforts to understand factors that contribute to women’s career development in STEM fields. Using social cognitive career theory (SCCT), this study examines how the interplay of individual and contextual factors (i.e., perfectionism and stereotype threat) contributes to the academic and career outcomes of women STEM students (i.e., self-efficacy, outcome expectation, interest, goals, and procrastination). Hypotheses regarding the relationships among these variables, as well as the moderating role of perfectionism on the mediated effect of stereotype threat on interest through self-efficacy were assessed. Data was collected from 323 …

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Data Compression In Multi-Hop Large-Scale Wireless Sensor Networks, Yimei Li May 2018

Data Compression In Multi-Hop Large-Scale Wireless Sensor Networks, Yimei Li

Open Access Dissertations

Data collection from a multi-hop large-scale outdoor WSN deployment for environmental monitoring is full of challenges due to the severe resource constraints on small battery-operated motes (e.g., bandwidth, memory, power, and computing capacity) and the highly dynamic wireless link conditions in an outdoor communication environment. We present a compressed sensing approach which can recover the sensing data at the sink with good accuracy when very few packets are collected, thus leading to a significant reduction of the network traffic and an extension of the WSN lifetime. Interplaying with the dynamic WSN routing topology, the proposed approach is efficient and simple …

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Geometric Measure Theory With Applications To Shape Optimization Problems, Qinfeng Li May 2018

Geometric Measure Theory With Applications To Shape Optimization Problems, Qinfeng Li

Open Access Dissertations

This thesis mainly focuses on geometric measure theory with applications to some shape optimization problems being considered over rough sets. We extend previous theory of traces for rough vector fields over rough domains and proved the compactness of uniform domains without uniformly bounded perimeter assumption. As application of these results, together with some other tools from geometric analysis, we can give partial results on the existence and uniqueness of minimizers of the nematic liquid droplets problem and the thermal insulation problem. Two other geometric minimization problems with averaged property, which include the generalized Cheeger set problem, are also studied.

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Horses In Agriculture Online: Designing, Developing, And Assessing Situational Interest An Online Museum Exhibit Using The Systems Approach Model Of Instructional Design, Elisa Anne Lofgren May 2018

Horses In Agriculture Online: Designing, Developing, And Assessing Situational Interest An Online Museum Exhibit Using The Systems Approach Model Of Instructional Design, Elisa Anne Lofgren

Open Access Dissertations

Research on motivations of learners has been done in traditional museum environments, but the research of online museum exhibits is in its infancy. While variables such as interactivity have been explored in traditional museum exhibits, little is still known about how these variables affect visitor experiences in online applications. It is important to know if the application of technology into these programs, such as online learning experiences and corresponding characteristics such as interactivity, free-choice use, and adaptive/adaptable e-learning effects the learner experience. This study follows a formal process of instructional design to develop an online educational resource to be used …

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Interplay Of Endogenous And Exogenous Biochemical Species On Neuropathic Pain After Spinal Cord Injury, Breanne Suzanne Muratori Butler May 2018

Interplay Of Endogenous And Exogenous Biochemical Species On Neuropathic Pain After Spinal Cord Injury, Breanne Suzanne Muratori Butler

Open Access Dissertations

Neuropathic pain after spinal cord injury (SCI) presents a complex clinical challenge, affecting millions with no satisfactory treatment options currently available. Much of the recent research focuses on a wide variety of endogenous mechanisms that can contribute to pain, but have yet to produce positive results in clinical studies. This dissertation focuses on the role of a highly reactive and toxic aldehyde, acrolein, in initiating, instigating, and perpetuating neuropathic pain after spinal cord injury. Acrolein is shown to mimic damage caused by an injury, in the absence of mechanical trauma. Additionally, removing it using acrolein scavengers can mitigate neuropathic pain-like …

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Modeling And Simulation Of Multiphase Flow Between Rotating And Stationary Disks, Irsha Pardeshi May 2018

Modeling And Simulation Of Multiphase Flow Between Rotating And Stationary Disks, Irsha Pardeshi

Open Access Dissertations

The Clutch in an automotive vehicle transfers power from the engine to the wheels with the speed and torque controlled by a gearbox. To accommodate different speeds and loads, different gear ratios are needed, and the clutch disengages and engages every time those ratios are changed. Since heat is generated when disengaged and when suddenly engaging, lubricating oil is pumped throughout the clutch to cool and to reduce friction. When the clutch is disengaged, drag torque is generated. Drag torque is due to the viscous force from the relative motion between the friction (rotating) disk and the separator (stationary) disk. …

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A Molecular Perspective For The Understanding Of Polymer‒Drug Interactions, Laura Isabel Mosquera Giraldo May 2018

A Molecular Perspective For The Understanding Of Polymer‒Drug Interactions, Laura Isabel Mosquera Giraldo

Open Access Dissertations

Polymers are often used to stabilize amorphous drug formulations enabling the maintenance of high drug supersaturations. However, the molecular mechanism of stabilization is unclear, making the rational design of new polymers challenging. This research has focused on understanding the effectiveness of polymers to inhibit drug crystallization using experimental and computational modeling approaches. This thesis has six sections. The first section reviews the pharmaceutical significance of amorphous solid dispersions. The second section describes a study to evaluate the phase behavior of supersaturated drug solutions of telaprevir, a compound that undergoes glass-liquid phase separation when the amorphous solubility is exceeded. The third …

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A Measure Of Human-Integrated System Performance Under Time-Varying Circumstances, Nguyen-Vang-Phuc Nguyen May 2018

A Measure Of Human-Integrated System Performance Under Time-Varying Circumstances, Nguyen-Vang-Phuc Nguyen

Open Access Dissertations

There are many methods to evaluate a system from given options in discrete or fixed situations (‘circumstance’). However, most systems are operated under time-varying circumstances and it’s not known how to evaluate the best system design when the operator in that system moves between time varying circumstances. In this dissertation, an adaptability model has been formalized using symbolic notion, which is based on learning curve theory and the adaptability measures are proposed. In the first study (‘the demonstration study’), the measures proved that they could be calculated and the learning curves could be plotted in continuous varying-circumstances. In the second …

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Human Rights Treaty Commitment And Compliance: A Machine Learning-Based Causal Inference Approach, Dan Sin Nguyen Vo May 2018

Human Rights Treaty Commitment And Compliance: A Machine Learning-Based Causal Inference Approach, Dan Sin Nguyen Vo

Open Access Dissertations

Why do states ratify international human rights treaties? How much do human rights treaties influence state behaviors directly and indirectly? Why are some human rights treaty monitoring procedures more effective than others? What are the most predictively and causally important factors that can reduce and prevent state repression and human rights violations? This dissertation provide answers to these keys causal questions in political science research, using a novel approach that combines machine learning and the structural causal model framework. The four research questions are arranged in a chronological order that refects the causal process relating to international human rights treaties, …

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Optical Signal Processing For Manipulating And Characterizing Time-Frequency Entangled Photons., Ogaga D. Odele May 2018

Optical Signal Processing For Manipulating And Characterizing Time-Frequency Entangled Photons., Ogaga D. Odele

Open Access Dissertations

Time-frequency entangled photons ("biphotons") exhibit joint spectral and temporal correlations that are unattainable with classical light. Besides being deployed for tests of quantum nonlocality, these photonic states are desirable for a unique range of applications that can significantly impact communications and computation. In this dissertation, we describe novel schemes based on spectral and temporal domain processing for manipulating and characterizing broadband biphotons. Implementing frequency-dependent filters, first, we present and demonstrate a technique for controlling the relative delay between a pair of entangled photons, relying on pump frequency tuning and the quantum concept of nonlocal dispersion cancellation. Next, we demonstrate near-field …

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Computational Optimization Of Networks Of Dynamical Systems Under Uncertainties: Application To The Air Transportation System, Jun Chen May 2018

Computational Optimization Of Networks Of Dynamical Systems Under Uncertainties: Application To The Air Transportation System, Jun Chen

Open Access Dissertations

To efficiently balance traffic demand and capacity, optimization of air traffic management relies on accurate predictions of future capacities, which are inherently uncertain due to weather forecast. This dissertation presents a novel computational efficient approach to address the uncertainties in air traffic system by using chance constrained optimization model. First, a chance constrained model for a single airport ground holding problem is proposed with the concept of service level, which provides a event-oriented performance criterion for uncertainty. With the validated advantage on robust optimal planning under uncertainty, the chance constrained model is developed for joint planning for multiple related airports. …

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Electrical, Thermoelectric, And Phase-Coherent Transport In Two-Dimensional Materials, Morteza Kayyalha May 2018

Electrical, Thermoelectric, And Phase-Coherent Transport In Two-Dimensional Materials, Morteza Kayyalha

Open Access Dissertations

Over the past few years there has been a growing interest in layered two dimensional (2D) materials such as graphene, transition metal dichalcogenides (TMDs), and three dimensional topological insulators (TIs). In this thesis, we experimentally study electrical, thermoelectric, and phase coherent transport in these 2D materials and work on three main projects. First, we investigate the low frequency (f) flicker (also called 1/f) noise of single-layer graphene devices on h-BN along with those on SiO2/Si. We observe that the devices fabricated on h-BN have on average one order of magnitude lower noise amplitude compared with devices fabricated on SiO2/Si despite …

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Understanding And Addressing Misconceptions In Introductory Programming: A Data-Driven Approach, Yizhou Qian May 2018

Understanding And Addressing Misconceptions In Introductory Programming: A Data-Driven Approach, Yizhou Qian

Open Access Dissertations

With the expansion of computer science (CS) education, CS teachers in K-12 schools should be cognizant of student misconceptions and be prepared to help students establish accurate understanding of computer science and programming. This exploratory design-based research (DBR) study implemented a data-driven approach to identify secondary school students’ misconceptions using both their compilation and test errors and provide targeted feedback to promote students’ conceptual change in introductory programming. Research subjects were two groups of high school students enrolled in two sections of a Java-based programming course in a 2017 summer residential program for gifted and talented students. This study consisted …

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Exact Solution Of The Dimer Model On The Square And Triangular Lattice, Dražen Petrovi¢ May 2018

Exact Solution Of The Dimer Model On The Square And Triangular Lattice, Dražen Petrovi¢

Open Access Dissertations

In this thesis we give an exact solution of the dimer model on the square and triangular lattice with different boundary conditions. Concretely, we being by discussing Kasteleyn’s contribution to the dimer model studies. We then prove the Pfaÿan Sign Theorem for the dimer model on a triangular lattice embedded in the torus. More specifcally, we prove that the Pfaffan of the Kasteleyn periodic-periodic matrix is negative, while the Pfaÿans of the Kasteleyn periodic-antiperiodic, antiperiodic-periodic, and antiperiodic-antiperiodic matrices are all positive. The proof is based on the Kasteleyn identities and on small weight expansions. Finally, we obtain the full asymptotic …

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Calderón's Musical Message: The Importance Of The Auditory Over The Visual, Laura Ramiro Moreno May 2018

Calderón's Musical Message: The Importance Of The Auditory Over The Visual, Laura Ramiro Moreno

Open Access Dissertations

Calderón de la Barca, a highly philosophical and religious playwright, focused the final part of his career on experimenting with musical court theater. My dissertation explains the motivation behind Calderón’s implementation of music in his theatrical productions and the situation that led him to create the new dramatic genre of zarzuela. This project analyzes the evolution of early modern musical theater in Spain by observing musical elements that are reflected in the text and related to characters and themes in the plays. A reflection on musical conventions in European theater, through the use of cognitive theories, studies on music and …

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Modeling And Optimization Of Dynamical Systems In Epidemiology Using Sparse Grid Interpolation, Aditya P. Sai May 2018

Modeling And Optimization Of Dynamical Systems In Epidemiology Using Sparse Grid Interpolation, Aditya P. Sai

Open Access Dissertations

Infectious diseases pose a perpetual threat across the globe, devastating communities, and straining public health resources to their limit. The ease and speed of modern communications and transportation networks means policy makers are often playing catch-up to nascent epidemics, formulating critical, yet hasty, responses with insufficient, possibly inaccurate, information. In light of these difficulties, it is crucial to first understand the causes of a disease, then to predict its course, and finally to develop ways of controlling it. Mathematical modeling provides a methodical, in silico solution to all of these challenges, as we explore in this work. We accomplish these …

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Semiclassical Resolvent Estimates And Wave Decay In Low Regularity, Jacob Z. Shapiro May 2018

Semiclassical Resolvent Estimates And Wave Decay In Low Regularity, Jacob Z. Shapiro

Open Access Dissertations

In this thesis, we prove weighted resolvent upper bounds for semiclassical Schr¨odinger operators. These upper bounds hold in the semiclassical limit. First, we consider operators in dimension two when the potential is Lipschitz with long range decay. We prove that the resolvent norm grows at most exponentially in the inverse semiclassical parameter, while near infinity it grows at most linearly. Both of these bounds are optimal. Second, we work in any dimension and require that the potential belong to L∞ and have compact support. Again, we find that the weighted resolvent norm grows at most exponentially, but this time with …

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Evaluation Of A Redesigned Chemistry Course Sequence For Undergraduate Life Science Majors, Carly Lynn Schnoebelen May 2018

Evaluation Of A Redesigned Chemistry Course Sequence For Undergraduate Life Science Majors, Carly Lynn Schnoebelen

Open Access Dissertations

In response to both nationwide calls for reform and a perception that the existing chemistry curriculum was not meeting the needs of life science students, faculty in the department of chemistry at Purdue created a redesigned chemistry course sequence specifically aimed at preparing biology majors. The new sequence, called the 1-2-1 curriculum, spans four semesters of instruction, including one semester of general chemistry, two semesters of organic chemistry, and one semester of biochemistry. The 1-2-1 curriculum was implemented in the 2013-2014 academic year, and students appeared to be progressing through successfully. However, there was a need for a more systematic …

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Synergistic Effects Of High Particle Fluxes And Transient Heat Loading On Material Performance In A Fusion Environment, Gregory Poppy Sinclair May 2018

Synergistic Effects Of High Particle Fluxes And Transient Heat Loading On Material Performance In A Fusion Environment, Gregory Poppy Sinclair

Open Access Dissertations

The work presented in this thesis focuses on the thermal and structural evolution of different materials when exposed to both high-flux ion irradiation and high intensity pulsed heat loading. Nuclear fusion devices create an intense radiation environment consisting of very energetic deuterium (D+) and helium (He+) ions. During operation, off-normal plasma events, such as edge-localized modes (ELMs), could cause intense heating of the plasma-facing component (PFC) surface, leading to melting and possible splashing into the fusion plasma. High-Z, refractory metals, such as tungsten (W), are therefore seen as favorable, due to their high melting point, high thermal conductivity, and low …

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Understanding And Improving The Non-Cognitive Factors That Affect First-Year Engineering Performance, Ryan Senkpeil May 2018

Understanding And Improving The Non-Cognitive Factors That Affect First-Year Engineering Performance, Ryan Senkpeil

Open Access Dissertations

To maintain America’s status as a global technological leader, there has been a longstanding effort to increase the quality and quantity of engineers in the workforce. Previous research and government reports have called on the education system at all levels to increase enrollment and persistence in college engineering programs. Additionally, engineering employers continue to be dissatisfied with the skills obtained by those students who do persist to graduation, in part because those students that may become the best engineers are leaving engineering. In order to effectively recruit and retain the best engineering students, the factors that affect engineering student success …

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Bayesian Nonparametrics To Model Content, User, And Latent Structure In Hawkes Processes, Xi Tan May 2018

Bayesian Nonparametrics To Model Content, User, And Latent Structure In Hawkes Processes, Xi Tan

Open Access Dissertations

Communication in social networks tends to exhibit complex dynamics both in terms of the users involved and the contents exchanged. For example, email exchanges or activities on social media may exhibit reinforcing dynamics, where earlier events trigger follow-up activity through multiple structured latent factors. Such dynamics have been previously represented using models of reinforcement and reciprocation, a canonical example being the Hawkes process (HP). However, previous HP models do not fully capture the rich dynamics of real-world activity. For example, reciprocation may be impacted by the significance and receptivity of the content being communicated, and modeling the content accurately at …

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Pre-Service Teachers' Understanding The Measurement Of The Area Of Rectangles, Cetin Kursat Bilir May 2018

Pre-Service Teachers' Understanding The Measurement Of The Area Of Rectangles, Cetin Kursat Bilir

Open Access Dissertations

Existing research has identified pre-service teachers’ (PTs’) difficulties with measuring the area of rectangles and explaining their approaches to area measurement. Yet, little is known about elementary PTs’ understandings of area measurement. Existing research has focused on children’s understanding of area measurement in the context of rectangles and has identified mental processes they use to construct area measurement. The study described in this report contributes to and extends this literature by exploring elementary PTs’ understandings of area measurement in the context of rectangles. Clinical interview methodology was used to investigate four PTs’ mental processes used in area measurement tasks. Study …

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