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- Creator:
- Hoffmann, Alex P.
- Description:
- Research Overview: In situ magnetic field measurements are often difficult to obtain due to the presence of stray magnetic fields generated by spacecraft electrical subsystems. The conventional solution is to implement strict magnetic cleanliness requirements and place magnetometers on a deployable boom. However, this method is not always feasible on low-cost platforms due to factors such as increased design complexity, increased cost, and volume limitations. To overcome this problem, we propose using the Quad-Mag CubeSat magnetometer with an improved Underdetermined Blind Source Separation (UBSS) noise removal algorithm. The Quad-Mag consists of four magnetometer sensors in a single CubeSat form-factor card that allows distributed measurements of stray magnetic fields. The UBSS algorithm can remove stray magnetic fields without prior knowledge of the magnitude, orientation, or number of noise sources. UBSS is a two-stage algorithm that identifies signals through cluster analysis and separates them through compressive sensing. We use UBSS with single source point (SSP) detection to improve the identification of noise signals and iteratively-weighted compressed sensing to separate noise signals from the ambient magnetic field. Using a mock CubeSat, we demonstrate in the lab that UBSS reduces four noise signals producing more than 100 nT of noise at each magnetometer to below the expected instrument resolution (near 5 nT). Additionally, we show that the integrated Quad-Mag and improved UBSS system works well for 1U, 2U, 3U, and 6U CubeSats in simulation. Our results show that the Quad-Mag and UBSS noise cancellation package enables high-fidelity magnetic field measurements from a CubeSat without a boom.
- Keyword:
- source separation, demixing, magnetometers, stray magnetic fields, noise removal, and cubesat
- Citation to related publication:
- Hoffmann, A. P., Moldwin, M. B., Strabel, B. P., & Ojeda, L. V. (2023). Enabling Boomless CubeSat Magnetic Field Measurements with the Quad-Mag Magnetometer and an Improved Underdetermined Blind Source Separation Algorithm. Journal of Geophysical Research: Space Physics, 128, e2023JA031662. https://doi-org.proxy.lib.umich.edu/10.1029/2023JA031662
- Discipline:
- Engineering
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- Creator:
- McCuen, Brett A.
- Description:
- We present a comprehensive statistical analysis of high-frequency transient-large-amplitude (TLA) magnetic perturbation events that occurred at 12 high-latitude ground magnetometer stations throughout solar cycle 24 from 2009 to 2019. TLA signatures are defined as one or more second-timescale dB/dt interval with magnitude ≥ 6 nT/s within an hour event window. This study characterizes high-frequency TLA events based on their spatial and temporal behavior as well as relation to auroral substorms, geomagnetic storm phases and nighttime geomagnetic disturbance events events (GMD). We show that TLA events occur primarily at nighttime and solely in the high-latitude region above 60 degrees geomagnetic latitude. The largest TLA events occurred more often in the declining phase of the solar cycle when solar wind velocity was higher and ring current activity was lower, suggesting association to high-speed flows caused by coronal holes and subsequent corotating interaction regions reaching Earth. TLA perturbations often occurred preceding or within the most extreme nighttime geomagnetic disturbance (GMD) events with 5-10 minute timescales, but the TLA intervals were often even more localized than the ~300 km effective radius of GMDs: occurring at only some of the stations at which GMDs occurred. We show that TLA-related GMD events can result from dipolarization fronts in the magnetotail and fast flows toward Earth and are closely temporally associated to poleward boundary intensifications (PBI) and auroral streamers. The highly localized behavior and connection to the most extreme GMD events suggests that TLA intervals are a ground manifestation of the features within rapid and complex ionospheric structures that can drive GICs.
- Keyword:
- geomagnetic field, high frequency, space weather, transient-large-amplitude, TLA, high frequency dB/dt, dB/dt search algorithm
- Citation to related publication:
- McCuen, B. A., Moldwin, M. B., Engebretson, M. J., Weygand, J. G., Nishimura, Y. (2023). A Statistical Analysis of High-frequency Transient-Large-Amplitude Geomagnetic Disturbance. [To be submitted to] Journal of Geophysical Research: Space Physics
- Discipline:
- Science
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- Creator:
- Brennan, Jonathan R.
- Description:
- These files contain the raw data and processing parameters to go with the paper "Hierarchical structure guides rapid linguistic predictions during naturalistic listening" by Jonathan R. Brennan and John T. Hale. These files include the stimulus (wav files), raw data (matlab format for the Fieldtrip toolbox), data processing paramters (matlab), and variables used to align the stimuli with the EEG data and for the statistical analyses reported in the paper.
- Keyword:
- linguistics, syntax, language, and eeg
- Citation to related publication:
- Brennan JR, Hale JT (2019) Hierarchical structure guides rapid linguistic predictions during naturalistic listening. PLoS ONE 14(1): e0207741. https://doi.org/10.1371/journal.pone.0207741
- Discipline:
- Social Sciences
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Bozo languages of Mali (spreadsheets, media)
User Collection
- Creator:
- Heath, Jeffrey G.
- Description:
- This collection will archive lexical spreadsheets, audio files, geographic information, images, and videos that complement the reference grammars in pdf and docx form in the collection “Bozo languages of Mali (documents)” that are archived in Deep Blue Documents ( https://dx.doi.org/10.7302/6632). See the “readme” for that collection and the introductory material in the reference grammars for general information about the languages and the fieldwork., The initial material archived in the present collection consists of audio files. They are recordings of narratives, interviews, and conversations. Some of them have been transcribed and are presented as appendices in the reference grammars. Others have not been transcribed; they are presented here in the hope that they can eventually be transcribed or at least listened to by native speakers. If the author is able to transcribe some of them in the future, the transcriptions will be added here (and to the Deep Blue Documents collection)., Many of the recordings, as well as most of the images and videos to be added to this collection, have been made by project assistant Minkailou Djiguiba. He has courageously traveled into Bozo-speaking zones, some of which are highly insecure, to do this work. In addition, he has been instrumental in recruiting and transporting Bozo speakers to the author’s base in Bobo Dioulasso where much of the grammatical and lexical work has been done., and The author’s fieldwork is supported by grant PD-1941828 (2020-2024) from the National Science Foundation, Documenting Endangered Languages program, which is also supported by the National Endowment for the Humanities.
- Keyword:
- Bozo, Jenaama, Cliffs, Kelenga, Tigemaxo, and Tiéyaxo
- Discipline:
- Humanities
9Works -
Central Mali documentary videos
User Collection
- Creator:
- Heath, Jeffrey G.
- Description:
- Short documentary videos of practical activities and cultural events of Dogon, Fulbe, Songhay, and Bangande ethnic groups of eastern Central Mali. The videos were byproducts of linguistic research on the local language. They are presented here in three formats: wmv, avi, and either qt or mov. See the "readme" files in each work for a summary of the videos in it. and The footage was shot with various digital cameras. The oldest videos (2010 and one or two from 2011) were edited using iMovie. The later videos were edited using AVS editing software. Several of the 2010 videos, referred to as "compilations," are simple sequences of short clips that combine to illustrate a complex activity such as extracting oil from nuts. The later videos are in more flowing documentary form with overlaid titles in English. In some cases, vocabulary from the relevant native language is included in the titles.
- Keyword:
- Mali and Dogon
- Citation to related publication:
- www.dogonlanguages.org
- Discipline:
- Humanities
8Works -
- Creator:
- University of Michigan Museum of Paleontology and CTEES
- Description:
- Reconstructed CT slices for tooth in bone fragment of Colognathus obscurus (University of Michigan Museum of Paleontology catalog number UMMP 7506) as a series of TIFF images. Raw projections are not included in this dataset. The reconstructed slice data from the scan are offered here as a series of unsigned 16-bit integer TIFF images. The upper left corner of the first image (*_0000.tif) is the XYZ origin.
- Keyword:
- Paleontology, Fossil, CT, Reptile, UMMP, University of Michigan Museum of Paleontology, Triassic, and bf7ead64-3fff-a3f2-6b15-d04548dae2da
- Discipline:
- Science
-
- Creator:
- Al Shidi, Qusai. and Pulkkinen, Tuija.
- Description:
- This is part of the simulation set of geomagnetic storms from 2010 to 2019. The Space Weather Modeling Framework (SWMF) with the configuration of SWPC v2 was used. The output files can be read by the visualization scripts included in the SWMF or the SpacePy Python package.
- Keyword:
- space weather, space physics, geomagnetic storms, and magnetosphere
- Discipline:
- Science
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- Creator:
- Lumeng, Julie C
- Description:
- Healthy full-term infants were enrolled in a longitudinal study designed to examine the development of infant eating behavior. Infant weight and length was measured, mothers completed questionnaires regarding infant eating behaviors, and infants were weighed and length measured at ages 1, 2, 4, 6 and 10 months. Trajectories of eating behaviors were identified using latent class growth modeling and bivariate analyses examined associations of infant eating behavior trajectory membership with infant and maternal characteristics. Cross-lagged analyses examined associations between BEBQ subscales and infant weight-for-length z-score.
- Keyword:
- infant, eating, weight gain, and feeding
- Citation to related publication:
- Harlan McCaffery, Julie Zaituna, Sophie Busch, Niko Kaciroti, Alison L. Miller, Julie C. Lumeng, Katherine L. Rosenblum, Ashley Gearhardt, Megan H. Pesch, Developmental trajectories of eating behaviors and cross-lagged associations with weight across infancy, Appetite, 2023, 106978
- Discipline:
- Health Sciences
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- Creator:
- Rivera-Rivera, Luis Y., Moore, Timothy C., and Glotzer, Sharon C.
- Description:
- The dataset is organized as follows: the data for each of the three target structures is contained within a directory with the structure name (e.g., kagome, pyrocholore and snub-square). Within each structure directory, data obtained from alchemical and self-assembly simulations are separated into alchem and self-assembly directories respectively. An additional suboptimal-self-assembly directory is only present for the snub-square structure and contains the data for the pattern registration analysis discussed in the SI. For a detailed description of each file contained within each directory, please refer to the README file.
- Keyword:
- inverse design, self-assembly, triblock Janus particles, crystallization slot, and digital alchemy
- Citation to related publication:
- Rivera-Rivera, LY, Moore, TC & SC Glotzer. Inverse design of triblock Janus spheres for self-assembly of complex structures in the crystallization slot via digital alchemy. Soft Matter, 2023, 19, 2726-2736 doi: 10.1039/d2sm01593e
- Discipline:
- Engineering
-
- Creator:
- Chenevert, Thomas L., Malyarenko, Dariya, Amouzandeh, Ghoncheh, Pickup, Stephen, Zhou, Rong, Manning, Henry Charles, Gamon, Seth T., Shoghi, Kooresh I., Quirk, James D., Sriram, Renuka, Larson, Peder, Lewis, Mickael T., Pautler, Robia G., Kinahan, Paul E., and Muzi, Mark
- Description:
- Goals of this work quantify repeatability and reproducibility across multiple NIH/NCI Co-Clinical Imaging Research Resources Program (CIRP) preclinical MRI systems in performing diffusion measurement using a standardized acquisition protocol on a shared phantom containing temperature-controlled medium of known diffusivity. To achieve these goals, the CIRP Image Acquisition Data Processing (IADP) working group (WG) performed a round-robin study of an ice water-based DWI phantom using a detailed phantom preparation procedure and standardized DWI acquisition protocol, with both site- and core-lab generated ADC measurements derived from shared datasets.
- Keyword:
- diffusion MRI, pre-clinical MRI, apparent diffusion coefficient (ADC), repeatability, reproducibility, and accuracy
- Citation to related publication:
- Tomography 2023, 9, 375–386. https://doi.org/10.3390/tomography9010030
- Discipline:
- Health Sciences