This research was completed to statistically validate that a data-model refinement technique could integrate real measurements to remove bias from physics-based models via changing the forcing parameters such as the thermal conductivity coefficients.
Ponder, B. M., Ridley, A. J., Goel, A., & Bernstein, D. S. (2023). Improving forecasting ability of GITM using data-driven model refinement. Space Weather, 21, e2022SW003290. https://doi.org/10.1029/2022SW003290
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.
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
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.
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
The IN were sampled during and after ICB and sequenced to identify gene expression signatures that correlated with sensitivity or resistance. We also analyzed gene expression at the IN prior to ICB treatment to identify markers predicting therapeutic response. Longitudinally interrogating an IN, to monitor changes associated with ICB response, presents a new opportunity to personalize care and investigate mechanisms underlying treatment resistance.
Statistical study of residuals between Swarm observations and IGRF-13 geomagnetic field model larger than 300 nT in northern and southern hemisphere. Data analysis done on https://viresclient.readthedocs.io/en/latest/
These data are generated to conduct a statistical study of the locations of large residuals in the two hemispheres for a better understanding of potential error in satellite aviation application when using Earth magnetic field models like IGRF as references, as well as the energy transfer in the magnetosphere-ionosphere-thermosphere coupling.
Interhemispheric asymmetries are found in the locations of the large residuals due to the difference in geographic pole locations.
Accurate prediction of physical alterations in carbonate reservoirs under dissolution is critical for development of subsurface energy technologies. The impact of mineral dissolution on flow characteristics depends on the connectivity and tortuosity of the pore network. Persistent homology is a tool from algebraic topology that describes the size and connectivity of topological features. When applied to 3D X-ray computed tomography (XCT) imagery of rock cores, it provides a novel metric of pore network heterogeneity. Prior works have demonstrated the efficacy of persistent homology in predicting flow properties in numerical simulations of flow through porous media. Its ability to combine size, spatial distribution, and connectivity information make it a promising tool for understanding reactive transport in complex pore networks, yet limited work has been done to apply persistence analysis to experimental studies on natural rocks. In this
study, three limestone cores were imaged by XCT before and after acid-driven dissolution flow through experiments. Each XCT scan was analyzed using persistent homology. In all three rocks, permeability increase was driven by the growth of large, connected pore bodies. The two most homogenous samples saw an increased effect nearer to the flow inlet, suggesting emerging preferential flow paths as the reaction front progresses. The most heterogeneous sample showed an increase in along-core homogeneity during reaction. Variability of persistence showed moderate positive correlation with pore body size increase. Persistence heterogeneity analysis could be used to anticipate where greatest pore size evolution may occur in a reservoir targeted for subsurface development, improving confidence in project viability.
The data in this repository is a nearly unique dataset at the time of its making -- precise measurements of all contact forces of a 6-legged robot during multi-legged slipping motions and regular walking. These data were collected to establish the validity of the observation presented in this article: Zhao et al. Walking is like slithering: A unifying, data-driven view of locomotion. (2022) PNAS 119(37): e113222119. DOI: https://doi.org/10.1073/pnas.2113222119
This dataset is part of a collection released in support of an IROS 2023 workshop publication, with a supporting website ( https://sites.google.com/umich.edu/novelsensors2023). To enable new research in the area of novel sensors for autonomous vehicles, these datasets are designed for the task of place recognition with novel sensors. To our knowledge, this new dataset is the first to include stereo thermal cameras together with stereo event cameras and stereo monochrome cameras, which perform better in low-light than RGB cameras., The dataset collection platform is a Ford Fusion vehicle with roof-mounted sensing suite, which consists of forward-facing stereo uncooled thermal cameras (FLIR Boson 640+ ADK), event cameras (iniVation DVXplorer), monochrome cameras (FLIR BFS-PGE-16S2M), and RGB cameras (FLIR BFS-PGE-50S5C) aligned with ground truth position from a high precision navigation system. Sequences include ~10 km routes, which may be driven repeatedly under varying lighting conditions and feature instances of direct sunlight and low-light that challenge conventional cameras., and A software toolkit to facilitate efficient use of the dataset including dataset download, application of calibration parameters, and evaluation of place recognition results based on standard metrics (e.g., maximum recall at 100% precision). These software tools for converting, managing, and viewing datafiles can be found at the associated GitHub repository ( https://github.com/umautobots/nsavp_tools).
This dataset is part of a collection released in support of an IROS 2023 workshop publication, with a supporting website ( https://sites.google.com/umich.edu/novelsensors2023). To enable new research in the area of novel sensors for autonomous vehicles, these datasets are designed for the task of place recognition with novel sensors. To our knowledge, this new dataset is the first to include stereo thermal cameras together with stereo event cameras and stereo monochrome cameras, which perform better in low-light than RGB cameras., The dataset collection platform is a Ford Fusion vehicle with roof-mounted sensing suite, which consists of forward-facing stereo uncooled thermal cameras (FLIR Boson 640+ ADK), event cameras (iniVation DVXplorer), monochrome cameras (FLIR BFS-PGE-16S2M), and RGB cameras (FLIR BFS-PGE-50S5C) aligned with ground truth position from a high precision navigation system. Sequences include ~10 km routes, which may be driven repeatedly under varying lighting conditions and feature instances of direct sunlight and low-light that challenge conventional cameras., and A software toolkit to facilitate efficient use of the dataset including dataset download, application of calibration parameters, and evaluation of place recognition results based on standard metrics (e.g., maximum recall at 100% precision). These software tools for converting, managing, and viewing datafiles can be found at the associated GitHub repository ( https://github.com/umautobots/nsavp_tools).
This data provided evidence of the presence of a lower hybrid drift instability in a magnetic nozzle. It was used in DOI: 10.1063/5.0012668 to estimate the effective electron collision frequency that it induced in the context of cross-field electron transport. It is also used to determine the effective reduction in heat flux resulting from propagation along magnetic field lines in an upcoming work.
Hepner, S., Jorns, B. (2020). Wave-driven non-classical electron transport in a low temperature magnetically expanding plasma. Appl. Phys. Lett, 116(263502). https://doi.org/10.1063/5.0012668