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The purpose of this research full paper is to investigate issues facing very early-stage master’s students as they transition into a degree program at a large research-intensive university. While there is an increasing focus on graduate and doctoral engineering education, few studies have sought to focus specifically on master’s students, treating them from a research perspective as miniature doctoral students, though it is documented that MS students in engineering have different goals and motivations for pursuing graduate study than PhD students, as well as different anticipated career trajectories. To further compound these gaps in the literature, most studies assume that doctoral students in engineering come from historically privileged socioeconomic backgrounds. National conversations are clear that to broaden participation in engineering, the educational community must attend to the specific needs of students from low-income backgrounds. These students may also not have access to the social and cultural capital required to navigate graduate school, since many are first-generation graduate students and because systems of education are traditionally designed for students from upper class backgrounds. To this end, this study explores the experiences of first-semester graduate students supported in part by funding aimed to support master’s students and have demonstrated unmet financial need. Interviews were conducted with six first- and second year master’s students and analyzed using thematic analysis methods employing Posselt’s Framework for Doctoral Student Support—here, extended to master’s students—to elicit information about surprises, expectations, and unanticipated issues facing this special population of students. Findings indicate that there are several easily implemented structural modifications programs and faculty can take that can facilitate the transition to graduate school for graduate students, low-income and otherwise.more » « lessFree, publicly-accessible full text available June 24, 2025
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We present a machine-learning approach to detect and analyze meteor echoes (MADAME), which is a radar data processing workflow featuring advanced machine-learning techniques using both supervised and unsupervised learning. Our results demonstrate that YOLOv4, a convolutional neural network (CNN)-based one-stage object detection model, performs remarkably well in detecting and identifying meteor head and trail echoes within processed radar signals. The detector can identify more than 80 echoes per minute in the testing data obtained from the Jicamarca high power large aperture (HPLA) radar. MADAME is also capable of autonomously processing data in an interferometer mode, as well as determining the target’s radiant source and vector velocity. In the testing data, the Eta Aquarids meteor shower could be clearly identified from the meteor radiant source distribution analyzed automatically by MADAME, thereby demonstrating the proposed algorithm’s functionality. In addition, MADAME found that about 50 percent of the meteors were traveling in inclined and near-inclined circular orbits. Furthermore, meteor head echoes with a trail are more likely to originate from shower meteor sources. Our results highlight the capability of advanced machine-learning techniques in radar signal processing, providing an efficient and powerful tool to facilitate future and new meteor research.
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Given the existential threat of climate change, we urge the heliophysics scientific community to consider ways in which we might further contribute to global efforts to address climate change. Whole atmosphere studies reveal that climate change processes impact even the uppermost regions of the atmosphere. The heliophysics research community now has models spanning the surface through the upper thermosphere and a diversity of observational datasets of the middle and upper atmosphere that span multiple decades. These studies indicate that the middle and upper atmosphere provide multiple vertical footprints for climate change and thus can contribute to an understanding of whole atmosphere climate change processes in the complex atmosphereland- ocean system. This white paper outlines recommendations for expansion of long-term data sets; simulations of climate with whole atmosphere models; engagement in collaborations with the tropospheric research community; and exploration of the possibility of heliophysics contributions to climate assessment efforts. Additionally, we recommend education and outreach efforts to help members of the wider community become more knowledgeable about climate change; support for efforts to increase the diversity of the heliophysics science community; support for international collaborations, and climate mitigation measures that our science community can implement to reduce greenhouse gas emissions from our research, education, and outreach activities.more » « less
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ABSTRACT This work presents the result of sporadic meteor radiant density distribution using the Arecibo 430 MHz incoherent scatter radar (ISR) located in Puerto Rico for the first time. Although numerous meteor studies have been carried out using the Arecibo ISR, meteoroid radiant density distribution has remained a mystery as the Arecibo radar cannot measure vector velocity. A numerical orbital simulation algorithm using dynamic programming and stochastic gradient descent is designed to solve the sporadic meteoroid radiant density and the corresponding speed distributions of the meteors observed at Arecibo. The data set for the algorithm comprises over 250 000 meteors from Arecibo observations between 2009 and 2017. Five of the six recognized sporadic meteor sources can be identified from our result. There is no clearly identifiable South Apex source. Instead, there is a broad distribution between +/−30° ecliptic latitude, with the peak density located in the North Apex direction. Our results also indicate that the Arecibo radar is not sensitive to meteors travelling straight into or perpendicular to the antenna beam but is most sensitive to meteors with an arrival angle between 30° and 60°. Our analysis indicates that about 75 per cent of meteoroids observed by the Arecibo radar travel in prograde orbits when the impact probability is considered. Most of the retrograde meteoroids travel in inclined low-eccentricity orbits.
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Abstract A novel computer vision‐based meteor head echo detection algorithm is developed to study meteor fluxes and their physical properties, including initial range, range coverage, and radial velocity. The proposed Algorithm for Head Echo Automatic Detection (AHEAD) comprises a feature extraction function and a Convolutional Neural Network (CNN). The former is tailored to identify meteor head echoes, and then a CNN is employed to remove false alarms. In the testing of meteor data collected with the Jicamarca 50 MHz incoherent scatter radar, the new algorithm detects over 180 meteors per minute at dawn, which is 2 to 10 times more sensitive than prior manual or algorithmic approaches, with a false alarm rate less than 1 percent. The present work lays the foundation of developing a fully automatic AI‐meteor package that detects, analyzes, and distinguishes among many types of meteor echoes. Furthermore, although initially evaluated for meteor data collected with the Jicamarca VHF incoherent radar, the new algorithm is generic enough that can be applied to other facilities with minor modifications. The CNN removes up to 98 percent of false alarms according to the testing set. We also present and discuss the physical characteristics of meteors detected with AHEAD, including flux rate, initial range, line of sight velocity, Signal‐to‐Noise Ratio, and noise characteristics. Our results indicate that stronger meteor echoes are detected at a slightly lower altitude and lower radial velocity than other meteors.
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Abstract Simultaneous OH(6,2) and O(1S) nightglow measurements obtained at the Andes Lidar Observatory (ALO) (30.3°S, 70.7°W) from September 2011 to April 2018 have been analyzed to investigate an unusual intensity pattern, that is, O(1S) nightglow intensity enhancement concurrent with OH(6,2) nightglow intensity weakening. We identified 142 nights showing that behavior during the ∼6.5‐year period. The data set comprised of these 142 nights displayed a semiannual occurrence rate with maxima during the equinoxes. A semidiurnal tide fitting applied to the 30‐min bin size monthly averaged data shows that the largest amplitudes of the tide occur in April–May and August–September in both OH(6,2) and O(1S). SABER atomic oxygen (O) climatology near ALO shows higher O densities near the equinoxes, with maximum O densities in March and September at ∼96 km. Lidar temperature analysis suggests that the O(1S) enhancement concurrent with the OH(6,2) weakening is often accompanied by a temperature increase at 96 km and a decrease at 87 km. Simulations using airglow models have also been carried out to investigate the effect of a long‐period oscillation on the OH(6,2) and O(1S) airglow intensities. A sensitivity study has also been conducted to illustrate the effect of the characteristics of a long‐period wave on the airglow intensity patterns.
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Abstract In this paper, a novel design and implementation of a software‐defined high‐frequency ionospheric radar, the Penn State Ionospheric Radar Imager (PIRI), is described. Furthermore, preliminary results produced by the system (located at 40.71° N, 77.97° W) are presented. PIRI is designed to be a modest and low‐cost radar system, which is composed mostly of commercial‐off‐the‐shelf products and utilizing open‐source software to perform pulse generation, pulse coding, downconversion, data acquisition, and signal processing. It is designed to be mobile, as it can easily be deployed at temporary locations to study local ionospheric disturbances. For the results presented herein, the radar operating frequency was 5.125 MHz. However, as the system is software defined and short active receive antennas are used, only the transmit antenna needs to be changed to operate over the entire high‐frequency (HF) band. The two orthogonal receive antennas enable both linear and circular polarization measurements. Peak transmit power of the system is 500 W. PIRI is designed to be a modest and cost‐effective alternative to the current standard HF ionospheric sounding systems and can be readily replicated.