151-160 of 238 results
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Statistical correlation study between solar wind, magnetosheath and plasma sheet properties
PI Heidi Nykyri
CO-I Xuanye Ma
Statistical study of the solar wind, magnetosheath, and magnetospheric plasma properties usinng 8+ years of THEMIS data.
The study will utilize recently developed statistical tool developed under Nykyri's NSF CAREER grant to present 8+ years of THEMIS spacecraft data in the coordinate system that takes into account the motion of the magnetopause and bow shock and will organize THEMIS observations into spatial bins with respect to physical boundaries under prevailing solar wind conditions. The study will address how do the plasma sheet properties such as number density, temperature, electron to ion temperature ratio and specific entropy vary during a) Parker-Spiral, Ortho-parker spiral, Northward and Southward IMF, and b) during high and slow solar wind speed, and how are these correlated with corresponding magnetosheath properties?
Categories: Faculty-Staff
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NSF Career Award: Effects of Magnetosheath properties on the dynamics and plasma transport produced by the Kelvin-Helmholtz Instability and on the Plasma Sheet Anisotropies
PI Heidi Nykyri
Project investigates impact of magnetosheath properties on Kelvin-Helmholtz instability
The magnetosheath processes will be studied by doing a statistical study of the magnetosheath properties using THEMIS data and by utilizing global hybrid (fluid electrons, particle ions) simulations. In addition, the MHD-scale KHI will be compared with hybrid and particle simulations of the instability.
Categories: Faculty-Staff
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Turbulence and Structure in the Magnetospheric Cusps: Cluster spacecraft observations
PI Heidi Nykyri
Project analyzes the structure, origin of fluctuations and high-energy particles in the high-altitude cusp regions
Project uses Cluster data and high-resolution local 3-D MHD simulations with test particles to determine the structure and origin of high-energy particles in the high-altitude cuspCategories: Faculty-Staff
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Magnetospheric Multi-Scale (MMS) Observations and simulations of high-energy electrons in the dayside magnetosheath
PI Heidi Nykyri
CO-I Brandon Burkholder
CO-I Xuanye Ma
The key objective of this study is to better understand the source and cause of high-energy electrons observed by the MMS in the dayside magnetosheath.
The key objective of this study is to better understand the source and cause of high-energy electrons observed by the MMS in the dayside magnetosheath. The Magnetospheric Multi-Scale (MMS) mission is a four-spacecraft constellation orbiting in formation around Earth with a main goal to study the microphysics of magnetic reconnection at the dayside magnetopause. Recent MMS observations showed high energy (40 keV) electrons leaking into the magnetosheath. However, the dominant leaking mechanism has not been fully understood. Global Lyon-Fedder-Mobarry (LFM) with test particle simulations suggest that low latitude reconnection and the nonlinear Kelvin-Helmholtz (KH) instability can cause the leak of high energy electrons into the magnetosheath. But it is important to notice that many of the electrons leaking events were observed close to Fall Equinox when the MMS orbit has a significant y-component and the z_GSM coordinate can be substantial (up to ~7 R_E). Therefore, MMS high-energy electron events may have a high-latitude source. For instance, it is well demonstrated that magnetic reconnection between the Interplanetary Magnetic Field (IMF) and Earth's magnetic field surrounding the cusps can lead to the formation of cusp diamagnetic cavities (Nykyri et al., JGR 2011a,b; Adamson et al., angeo 2011), extended regions of decreased magnetic field, which can be filled with higher energy (>30 keV) electrons, protons and O+ ions. Cluster observations revealed 90-degree pitch angle electrons in the cavity, strongly suggestive of a local acceleration mechanism (Walsh, angeo 2010; Nykyri et al, JASTP 2012). Test particle simulations in a high-resolution 3D cusp model uncovered that trapped particles in the diamagnetic cavities can be accelerated when their drift paths go through regions of "reconnection quasi-potential" (Nykyri et al, JASTP 2012). Once the IMF orientation changes it is possible for trapped particles in the cavity to end up into the loss cone and "leak out" of the cavity. A systematic approach to our science objective addresses the following compelling science questions by synergy using MMS observational data and numerical simulation.
Categories: Faculty-Staff
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Science and engineering proof of concept study for the Next generation Space Weather Prediction mission and space weather model development
PI Heidi Nykyri
Project analyzes astrodynamics (transfer trajectories) and spacecraft constellation stability about all Lagrange points for Mercury, Venus, Earth, Mars system for the "next generation" space weather prediction mission, and develops a solar wind model which will use data from this mission
Project analyzes astrodynamics and constellation stability for the "next generation" space weather prediction mission, and develops a solar wind model which will use data from this missionCategories: Faculty-Staff
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On The Origin and Transport of Energetic Particles
PI Heidi Nykyri
CO-I Xuanye Ma
Understanding the properties, origin and dynamics of energetic particles in the solar wind and magnetosphere is crucial for safe unmanned and manned space operations. This project will unravel the birth-mechanism of the source population of the Earth's radiation belts.
Understanding the properties, origin and dynamics of energetic particles in the solar wind and magnetosphere is crucial for safe unmanned and manned space operations. Therefore, energetic particles have attracted attention from the space physics community for decades. However, different regions and energy ranges of energetic particles may have their own unique origin and role for magnetospheric dynamics, which have not been fully explored and deserve to be investigated case by case. For instance, MMS recently observed dispersionless micro-injections in the 30-300 keV electrons accompanied by strong anisotropic ion temperature at the high-latitude magnetospheric boundary layer in the vicinity of the exterior southern cusp. Due to the different magnetic field geometry, these high-latitude microinjections could have a totally different origin than the typical low-latitude microinjections. Because this region is close to the radiation belts, ionosphere, and magnetosheath, these high-latitude microinjections could be the ~ tens to hundreds of keV seed population of the radiation belts, as well as leak into the ionosphere or into the magnetosheath. This project will unravel the birth-mechanism of the source population of the Earth's radiation belts.Categories: Faculty-Staff
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Experimental Identification of Plasma Wave Modes
PI Heidi Nykyri
CO-I Rachel Rice
Project uses MMS data to identify plasma wave modes contributing to the heating of the magnetospheric boundary layer
Projects uses single and multi-spacecraft data-analysis techniques to experimentally identify various plasma modes at different frequencies and assess their contribution to plasma heatingCategories: Faculty-Staff
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Predicting Pilot Misperception of Runway Excursion Risk Through Machine Learning Algorithms of Recorded Flight Data
PI Edwin Odisho
CO-I Dothang Truong
The research used predictive models to determine pilot misperception of runway excursion risk associated with unstable approaches. The Federal Aviation Administration defined runway excursion as a veer-off or overrun of the runway surface. The Federal Aviation Administration also defined a stable approach as an aircraft meeting the following criteria: (a) on target approach airspeed, (b) correct attitude, (c) landing configuration, (d) nominal descent angle/rate, and (e) on a straight flight path to the runway touchdown zone. Continuing an unstable approach to landing was defined as Unstable Approach Risk Misperception in this research. A review of the literature revealed that an unstable approach followed by the failure to execute a rejected landing was a common contributing factor in runway excursions.
Flight Data Recorder data were archived and made available by the National Aeronautics and Space Administration for public use. These data were collected over a four-year period from the flight data recorders of a fleet of 35 regional jets operating in the National Airspace System. The archived data were processed and explored for evidence of unstable approaches and to determine whether or not a rejected landing was executed. Once identified, those data revealing evidence of unstable approaches were processed for the purposes of building predictive models.
SAS™ Enterprise MinerR was used to explore the data, as well as to build and assess predictive models. The advanced machine learning algorithms utilized included: (a) support vector machine, (b) random forest, (c) gradient boosting, (d) decision tree, (e) logistic regression, and (f) neural network. The models were evaluated and compared to determine the best prediction model. Based on the model comparison, the decision tree model was determined to have the highest predictive value.
The Flight Data Recorder data were then analyzed to determine predictive accuracy of the target variable and to determine important predictors of the target variable, Unstable Approach Risk Misperception. Results of the study indicated that the predictive accuracy of the best performing model, decision tree, was 99%. Findings indicated that six variables stood out in the prediction of Unstable Approach Risk Misperception: (1) glideslope deviation, (2) selected approach speed deviation (3) localizer deviation, (4) flaps not extended, (5) drift angle, and (6) approach speed deviation. These variables were listed in order of importance based on results of the decision tree predictive model analysis.
The results of the study are of interest to aviation researchers as well as airline pilot training managers. It is suggested that the ability to predict the probability of pilot misperception of runway excursion risk could influence the development of new pilot simulator training scenarios and strategies. The research aids avionics providers in the development of predictive runway excursion alerting display technologies.
Categories: Graduate
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Examining and addressing the content knowledge development needs of Florida's aspiring and newly-qualified mathematics teachers
PI Catherine Paolucci
CO-I Darryl Chamberlain
CO-I Christopher Redding
CO-I Sam Vancini
CO-I Ashley Reese
This project aims to support content knowledge development for secondary mathematics teachers, particularly those whose pathway to certification has included limited post-secondary studies of mathematics.
This project aims to support content knowledge development for secondary mathematics teachers, particularly those whose pathway to certification has included limited post-secondary studies of mathematics. Initially, it will focus on teachers in Florida who do not have a degree in mathematics or a relevant field and have earned temporary certification by taking the 6-12 Mathematics Subject Area Exam (SAE-Math). Longer term, it aims to serve teachers with similar backgrounds on a national level.
Researchers recognize mathematical knowledge as an influential factor in teachers’ classroom practice (Ball, Thames & Phelps, 2008; Goldsmith, Doerr, & Lewis, 2014; Lampert, 2001) and have established the potential for advanced mathematical studies to positively impact their mathematical knowledge for teaching (Paolucci, 2015). Therefore, it is reasonable to expect teachers with little or no mathematical studies beyond their own K-12 mathematics education to require support similar to that needed by out-of-field mathematics teachers – qualified teachers assigned to teach mathematics when it does not match their subject area training (Hobbs & Törner, 2019; Ní Ríodáin, Paolucci, & O’Dwyer, 2017). This is of particular concern given links between out-of-field teaching and teacher quality and research suggesting that teachers most often teach out of field in schools where students are already underserved (Ingersoll, 2002; Nguyen & Redding, 2018).
In Florida, aspiring mathematics teachers with undergraduate degrees in unrelated fields can still earn temporary certification by passing the SAE-Math, which allows them to immediately begin teaching. Many then enroll in programs designed to meet professional certification requirements (e.g. UF’s Educator Preparation Institute (EPI)); however, because they have passed the SAE-Math, no content-focused coursework is required. As a result, preparation for the SAE-Math can be the primary means by which they develop the content knowledge needed to teach, prior to entering the classroom.
With this in mind, this project aims to examine the content knowledge development needs of Florida’s temporarily certified mathematics teachers, with a focus on those who were required to take the SAE-Math because they did not have an undergraduate degree in or related to mathematics. The following short-term goals apply to work expected to be completed during the 12-month CRIF funding period:
Goal 1: Establish baseline trends in the mathematical backgrounds, knowledge, and experiences of Florida’s aspiring and newly-certified mathematics teachers to better understand their content knowledge development needs.
This is valuable information for mathematics teacher educators and teacher education programs throughout Florida committed to offering professional certification pathways that better support content knowledge development.
Goal 2: Create an online dynamic assessment tool that addresses gaps and weaknesses in alternatively- certified teachers’ content preparation and supports content knowledge development aligned with Florida’s B.E.S.T. standards.
Outcomes from these two goals will inform preparation of a federal funding proposal with the following long-term goals that build on the work completed during the CRIF funding period:
Goal 3: Expand and measure the statewide impact of the dynamic assessment tool through partnership with school districts and institutions currently offering Florida’s 24 state-approved EPI programs.
Goal 4: Scale implementation and impact measurement to a national level through analysis of other state certification exams that can inform online learning tools for a range of certification pathways and programs designed to support out-of-field teachers (e.g. Teach for America).
Findings from this research will contribute to two areas of mathematics education research – understanding and addressing the needs of out-of-field mathematics teachers (Hobbs & Törner, 2019; Ní Ríodáin et al., 2017) and teachers’ development of the specialized content knowledge that has been linked to classroom practice (Ball et al., 2008). It is also likely to have state and policy implications for teacher education. In particular, the research will contribute insight to an ongoing international debate about the amount and nature of the mathematics content that should be required for teacher preparation.
An array of theoretical frameworks concerning the knowledge required for teaching mathematics have been developed by key researchers in the area (e.g. Ball et al., 2008; Davis & Renert, 2013; Rowland & Ruthven, 2011; Tatto et al., 2012). Such models provide guidance for designing experiences that target teacher knowledge development (Chapman, 2013), and particularly in this context, thinking about the development alternatively certified mathematics teachers. This project will incorporate and build on this work. The findings will also be valuable for mathematics teacher education in Florida as the state shifts to its new B.E.S.T. state standards in 2022.
Categories: Faculty-Staff
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Mobile Technology in Higher Education: An Extended Technology Acceptance Perspective
PI Dennis Pires
PI Leila Halawi
The study provides an important theoretical framework for decision-making for educational institutions as they seek improvement in user acceptance of technology in the higher education setting. The study adds to the knowledge in the field of information technology by providing statistical research that uses path analysis to disentangle the various causal processes underlying the acceptance of technology in higher education. In this study, the research addresses the following question: Are the constructs of perceived resources, perceived ease of use, perceived usefulness, and attitude towards use significant predictors of educators’ acceptance of mobile technology in higher education as defined by actual use?
The objective of this research study is to study the mobile technology acceptance of educators in the higher education industry in the United States. This study will utilize the Chen et al. (2013) extended technology acceptance model, that extended the original Davis (1989) TAM. In this research study, Chen et al. (2013) survey instrument will provide the necessary tool to collect data. Preliminary results show statistical significance exist in relationships across the assessed factors of perceived usefulness, perceived ease of use, perceived usefulness, attitude toward use, and behavioral intention, that contribute to the acceptance of mobile technology in higher education. The implications of the study are that institutions face a challenging task to understand the technology acceptance of educators as they incorporate the use of mobile technology to support their work and improve instructional practices. (Chen, B., Sivo, S., Seilhamer, R., Sugar, A., & Mao, J., 2013) and (Davis, F. D., 1989).
Categories: Faculty-Staff
151-160 of 238 results