Search Constraints
Number of results to display per page
View results as:
Search Results
-
- Creator:
- Sun, Hu, Ren, Jiaen, Chen, Yang, Zou, Shasha, Chang, Yurui, Wang, Zihan, and Coster, Anthea
- Description:
- Our research focuses on providing a fully-imputed map of the worldwide total electron content with high resolution and spatial-temporal smoothness. We fill in the missing values of the original Madrigal TEC maps via estimating the latent feature of each latitude and local time along the 2-D grid and give initial guess of the missing regions based on pre-computed spherical harmonics map. The resulting TEC map has high imputation accuracy and the ease of reproducing. All data are in HDF5 format and are easy to read using the h5py package in Python. The TEC map is grouped in folders based on years and each file contains a single-day data of 5-min cadence. Each individual TEC map is of size 181*361. and WARNING: 2023-12-01 the data file for 2019-Jan-03 has badly fitted values. Please avoid using it. All other days' files are ready to use.
- Keyword:
- Total Electron Content, Matrix Completion, VISTA, Spherical Harmonics, and Spatial-Temporal Smoothing
- Citation to related publication:
- Sun, H., Hua, Z., Ren, J., Zou, S., Sun, Y., & Chen, Y. (2022). Matrix completion methods for the total electron content video reconstruction. The Annals of Applied Statistics, 16(3), 1333-1358., Sun, H., Chen, Y., Zou, S., Ren, J., Chang, Y., Wang, Z., & Coster, A. (2023). Complete Global Total Electron Content Map Dataset based on a Video Imputation Algorithm VISTA. Scientific Data, in press., and Zou, S., Ren, J., Wang, Z., Sun, H., & Chen, Y. (2021). Impact of storm-enhanced density (SED) on ion upflow fluxes during geomagnetic storm. Frontiers in Astronomy and Space Sciences, 8, 746429.
- Discipline:
- Science and Engineering
-
- Creator:
- Klinich, Kathleen D, Lin, Brian, and Moore, Jamie L.
- Description:
- This dataset allows comparison of the different strategies implemented by vehicle manufacturers being used to communicate with drivers. Spreadsheets were created in MS Excel to summarize data for each vehicle, and include page numbers in each vehicle owner's manual for reference. The photos taken of each vehicle control panel allow detailed inspection of the displays and controls.
- Keyword:
- vehicle, controls, displays, and FMVSS 101
- Discipline:
- Engineering
-
- Creator:
- Brian, Chen
- Description:
- The procedure followed while creating this data is summarized in Section II of Chen, Brian, et al. "Behavioral cloning in atari games using a combined variational autoencoder and predictor model." 2021 IEEE Congress on Evolutionary Computation (CEC). IEEE, 2021. This data is not a result of a research but an intermediate product that is used in research. This dataset is generated to train a behavioral cloning framework from gameplay screen captures and keystrokes of an "expert" player. The RL agent that is trained using "RL Baselines Zoo package" acts as the "expert" player, whose decision making process we desire to learn. In addition to behavioral cloning experiments, this dataset is further used to demonstrate the efficacy of a novel incremental tensor decomposition algorithm on image-based data streams.
- Keyword:
- Imitation Learning, Behavioral Cloning, Reinforcement Learning, Machine Learning, and Gameplay Data
- Citation to related publication:
- Chen, Brian, et al. "Behavioral cloning in atari games using a combined variational autoencoder and predictor model." 2021 IEEE Congress on Evolutionary Computation (CEC). IEEE, 2021., Aksoy, Doruk, et al. "An Incremental Tensor Train Decomposition Algorithm." arXiv preprint arXiv:2211.12487 (2022)., and Chen, Brian, et al. "Low-Rank Tensor-Network Encodings for Video-to-Action Behavioral Cloning", forthcoming
- Discipline:
- Engineering and Science
-
- Creator:
- Gill, Tate M, Sercel, Christopher L, and Jorns, Benjamin A
- Description:
- Rotating Magnetic Field (RMF) thrusters are a form of electrodeless plasma propulsion. This technology is a low maturity but potentially enabling candidate for high-power in-space propulsion for use with alternative propellants. The purpose of the data here, and the associated publication is to evaluate the phenomenological efficiency modes for this thruster test article to explain and understand its overall efficiency. These modes include divergence, power coupling, mass utilization, and plasma/acceleration efficiency. Additional time-resolved measurements of the internal plasma properties were performed using a triple Langmuir probe to evaluate energy loss processes within the thruster.
- Keyword:
- Electric Propulsion, Rotating Magnetic Field Thrusters, Inductive Pulsed Plasma Thrusters, and Magnetic Nozzles
- Citation to related publication:
- Gill, T.M., Sercel, C.L., and Jorns, B.A., "Experimental Investigation into Efficiency Loss in Rotating Magnetic Field Thrusters", Plasma Sci. Sources and Tech. 2023 (In Review)
- Discipline:
- Engineering
-
- Creator:
- Brenner, Austin M
- Description:
- Results of computer simulation of near Earth space is looked at in a new way to understand how energy moves around the global system. It is found that in addition to a pathway of energy from the outside into the system and back again there is an internal loop which recirculates energy. These new methods will greatly improve our understanding how the whole magnetosphere system evolves and will help address evolution of processes that have space weather impacts.
- Keyword:
- Energy flux, geospace, magnetopause, magnetosphere, poynting flux, and reconnection
- Citation to related publication:
- Austin Brenner, Tuija I. Pulkkinen, Qusai Al Shidi, et al. Dissecting Earth’s Magnetosphere: 3D Energy Transport in a Simulation of a Real Storm Event. ESS Open Archive . August 04, 2023.
- Discipline:
- Science and Engineering
-
- Creator:
- Hung, Adam, Enninful Adu, Challen, and Moore, Talia Y.
- Description:
- The CAD files can be opened by any CAD software. The code is in Arduino and Python. The URDF was generated using Solidworks.
- Keyword:
- robotics, omnidirectional, tripod, ballbot, gliding, and rolling
- Citation to related publication:
- Hung, A., Enninful Adu, C., Moore, T.Y. (in review), SKOOTR: A SKating, Omni-Oriented, Tripedal Robot for dynamically stable indoor navigation. IEEE ICRA
- Discipline:
- Engineering
-
- Creator:
- Towne, Aaron, Yeh, Chi-An., Patel, Het, and Taira, Kunihiko
- Description:
- This dataset contains data from a three-dimensional large eddy simulation of Mach 0.3 flow over a NACA 0012 airfoil at Reynolds number 23,000, which features a transitional boundary layer, separation over a recirculation bubble, and a turbulent wake. The dataset contains 16,000 time-resolved snapshots of the mid-span and spanwise-averaged velocity fields. All data are stored within hdf5 files, and a Matlab script showing how the data can be read and manipulated is provided. Please see the ‘airfoilLES_README.pdf’ file for more information. We recommend using the ‘airfoilLES_example.zip’ file as an entry point to the dataset. and The dataset is part of “A database for reduced-complexity modeling of fluid flows” (see references below) and is intended to aid in the conception, training, demonstration, evaluation, and comparison of reduced-complexity models for fluid mechanics. The paper introduces the flow setup and computational methods, describes the available data, and provides an example of how these data can be used for reduced-complexity modeling. Users of these data should cite the papers listed below.
- Citation to related publication:
- Towne, A., Dawson, S., Brès, G. A., Lozano-Durán, A., Saxton-Fox, T., Parthasarthy, A., Biler, H., Jones, A. R., Yeh, C.-A., Patel, H., Taira, K. (2022). A database for reduced-complexity modeling of fluid flows. AIAA Journal 61(7): 2867-2892. and Yeh, C.-A. and Taira, K. (2019) Resolvent-analysis-based design of airfoil separation control. Journal of Fluid Mechanics, 867:572–610.
- Discipline:
- Science and Engineering
-
- Creator:
- Towne, Aaron, Jones, Anya, and Biler, Hulya
- Description:
- This dataset contains experimental measurements of a flat-plate airfoil passing through a large-amplitude transverse gust. The dataset contains an ensemble of of the airfoil-gust encounter to account for variability in the gust profile, and each realization contains time-resolved force measurements and planar PIV velocity fields. All data are stored within hdf5 files, and a Matlab script showing how the data can be read and manipulated is provided. Please see the ‘airfoilEXP_README.pdf’ file for more information. We recommend using the ‘airfoilEXP_example.zip’ file as an entry point to the dataset. and The dataset is part of “A database for reduced-complexity modeling of fluid flows” (see references below) and is intended to aid in the conception, training, demonstration, evaluation, and comparison of reduced-complexity models for fluid mechanics. The paper introduces the flow setup and computational methods, describes the available data, and provides an example of how these data can be used for reduced-complexity modeling. Users of these data should cite the papers listed below.
- Keyword:
- fluid mechanics and aerodynamics
- Citation to related publication:
- Towne, A., Dawson, S., Brès, G. A., Lozano-Durán, A., Saxton-Fox, T., Parthasarthy, A., Biler, H., Jones, A. R., Yeh, C.-A., Patel, H., Taira, K. (2022). A database for reduced-complexity modeling of fluid flows. AIAA Journal 61(7): 2867-2892., Biler, H., Sedky, G., Jones, A. R., Saritas, M. and Cetiner, O. (2021) Experimental investigation of transverse and vortex gust encounters at low Reynolds numbers. AIAA Journal, 59(3):786–799., and Andreu-Angulo, I., Babinsky, H., Biler, H., Sedky, G. and Jones, A. R. (2020) Effect of transverse gust velocity profiles. AIAA Journal, 58(12):5123–5133.
- Discipline:
- Science and Engineering
-
- Creator:
- Towne, Aaron and Dawson, Scott
- Description:
- This dataset contains data from direct numerical simulations of two-dimensional stationary and pitching flat-plate airfoils at Reynolds number 100. The dataset contains time-resolved snapshots of the velocity field, lift and drag coefficients, and airfoil kinematics spanning 40-100 convective time units. Cases include a stationary airfoil and eight different pitching frequencies. All data are stored within hdf5 files, and a Matlab script showing how the data can be read and manipulated is provided. Please see the ‘airfoilDNS_README.pdf’ file for more information. We recommend using the ‘airfoilDNS_example.zip’ file as an entry point to the dataset. and The dataset is part of “A database for reduced-complexity modeling of fluid flows” (see references below) and is intended to aid in the conception, training, demonstration, evaluation, and comparison of reduced-complexity models for fluid mechanics. The paper introduces the flow setup and computational methods, describes the available data, and provides an example of how these data can be used for reduced-complexity modeling. Users of these data should cite the papers listed below.
- Keyword:
- fluid mechanics and aerodynamics
- Citation to related publication:
- Towne, A., Dawson, S., Brès, G. A., Lozano-Durán, A., Saxton-Fox, T., Parthasarthy, A., Biler, H., Jones, A. R., Yeh, C.-A., Patel, H., Taira, K. (2022). A database for reduced-complexity modeling of fluid flows. AIAA Journal 61(7): 2867-2892. and Dawson, S. T. M., Floryan, D. C., Rowley, C. W., and Hemati, M. S. (2016) Lift enhancement of high angle of attack airfoils using periodic pitching. AIAA Paper 2016-2069.
- Discipline:
- Engineering and Science
-
- Creator:
- Towne, Aaron S. and Brès, Guillaume
- Description:
- This dataset contains data from a large eddy simulation of a turbulent jet at Mach number 0.9. The dataset contains 10000 time-resolved snapshots of three-dimensional velocity, density, and pressure fields spanning 2000 acoustic time units and also includes pre-processed azimuthal Fourier modes for each snapshot and the mean flow. All data are stored within hdf5 files, and a Matlab script showing how the data can be read and manipulated is provided. Please see the ‘jet_README.pdf’ file for more information. We recommend using the ‘jet_example.zip’ file as an entry point to the dataset. and The dataset is part of “A database for reduced-complexity modeling of fluid flows” (see references below) and is intended to aid in the conception, training, demonstration, evaluation, and comparison of reduced-complexity models for fluid mechanics. The paper introduces the flow setup and computational methods, describes the available data, and provides two examples of how these data can be used for reduced-complexity modeling. Users of these data should cite the two papers listed below.
- Keyword:
- fluid mechanics, jets, and turbulence
- Citation to related publication:
- Towne, A., Dawson, S., Brès, G. A., Lozano-Durán, A., Saxton-Fox, T., Parthasarthy, A., Biler, H., Jones, A. R., Yeh, C.-A., Patel, H., Taira, K. (2022). A database for reduced-complexity modeling of fluid flows. AIAA Journal 61(7): 2867-2892. and Brès, G. A., Jordan, P., Jaunet, V., Le Rallic, M., Cavalieri, A. V. G., Towne, A., Lele, S. K., Colonius, T., Schmidt, O. T. (2018) Importance of the nozzle-exit boundary-layer state in subsonic turbulent jets. J. Fluid Mech., 851:83–124.
- Discipline:
- Engineering and Science
-
- Creator:
- Burgin, Tucker and Mayes, Heather B.
- Description:
- This project aimed to discover and analyze the molecular mechanism of synthesis of two particular fucosylated oligosaccharide products in a mutant enzyme, Thermatoga maratima Alpha-L-Fucosidase D224G, whose wild type performs the opposite reaction (cleavage of fucosyl glycosidic bonds). Discovery of the mechanism was performed using an unbiased simulations method known as aimless shooting, whereas analysis of the mechanism in terms of the energy profile was performed using a separate method known as equilibrium path sampling. The data here concerns the latter method. and The contents of the atesa_master.zip are the ATESA GitHub project. A Python program for automating transition path sampling with aimless shooting using Amber. https://github.com/team-mayes/atesa
- Keyword:
- Equilibrium Path Sampling, Transition Path Sampling, Enzymatic Mechanism, and GH29
- Citation to related publication:
- Burgin, T., & Mayes, H. B. (2019). Mechanism of oligosaccharide synthesis via a mutant GH29 fucosidase. Reaction Chemistry & Engineering, 4(2), 402–409. https://doi.org/10.1039/C8RE00240A
- Discipline:
- Engineering
-
- Creator:
- Ruas, Terry, Ferreira, Charles H. P., Grosky, William, França, Fabrício O., and Medeiros, Débora M. R,
- Description:
- The relationship between words in a sentence often tell us more about the underlying semantic content of a document than its actual words, individually. Recent publications in the natural language processing arena, more specifically using word embeddings, try to incorporate semantic aspects into their word vector representation by considering the context of words and how they are distributed in a document collection. In this work, we propose two novel algorithms, called Flexible Lexical Chain II and Fixed Lexical Chain II that combine the semantic relations derived from lexical chains, prior knowledge from lexical databases, and the robustness of the distributional hypothesis in word embeddings into a single decoupled system. In short, our approach has three main contributions: (i) unsupervised techniques that fully integrate word embeddings and lexical chains; (ii) a more solid semantic representation that considers the latent relation between words in a document; and (iii) lightweight word embeddings models that can be extended to any natural language task. Knowledge-based systems that use natural language text can benefit from our approach to mitigate ambiguous semantic representations provided by traditional statistical approaches. The proposed techniques are tested against seven word embeddings algorithms using five different machine learning classifiers over six scenarios in the document classification task. Our results show that the integration between lexical chains and word embeddings representations sustain state-of-the-art results, even against more complex systems. Github: https://github.com/truas/LexicalChain_Builder
- Keyword:
- document classification, lexical chains, word embeddings, synset embeddings, chain2vec, and natural language processing
- Citation to related publication:
- Terry Ruas, Charles Henrique Porto Ferreira, William Grosky, Fabrício Olivetti de França, Débora Maria Rossi de Medeiros, "Enhanced word embeddings using multi-semantic representation through lexical chains", Information Sciences, 2020, https://doi.org/10.1016/j.ins.2020.04.048
- Discipline:
- Other, Science, and Engineering
-
- Creator:
- Chaoran Xu, Davlasheridze, Meri, Nelson-Mercer, Benjamin T., Bricker, Jeremy D., Jia, Jianjun, and Ross, Ashley D.
- Description:
- Hurricane Ike, which struck the United States in September 2008, was the ninth most expensive hurricane in terms of damages. It caused nearly $30 billion in damage, of which nearly $12B were insured losses, after making landfall on the Bolivar Peninsula, Texas. We used the Delft3d-FM/SWAN hydrodynamic and spectral wave model to simulate the storm surge inundation around Galveston Bay during Hurricane Ike. Damage curves were established through the eight hydrodynamic parameters (water depth, flow velocity, unit discharge, flow momentum flux, significant wave height, wave energy flux, total water depth (flow depth plus wave height), and total (flow plus wave) force) simulated by the model. We found that the damage curves are sensitive to the model grid resolution, building elevation, and the number of stories.
- Citation to related publication:
- Xu et al. (2023). Damage curves derived from Hurricane Ike in the west of Galveston Bay based on insurance claims and hydrodynamic simulations.
- Discipline:
- Engineering
-
- Creator:
- Mohtat, Peyman, Siegel, Jason B., and Stefanopoulou, Anna G.
- Description:
- The goal here is to study the voltage and expansion response of lithium-ion batteries at different charging rates. Specifically, the goal is to capture the observation of the smoothing of the peaks in dV/dQ and retention of the peaks in d^2 (backslash)delta/dQ^2 at higher C-rates. The retention of the peaks at higher charging rates enables better estimation of the cell capacity. To achieve this goal a reduced order electrochemical and mechanical model with multiple particles with a size distribution is developed. This allows us to capture the smoothing and preservation of the phase transitions in the voltage and expansion measurements at high C-rates, respectively. The model is written in Matlab software.
- Keyword:
- Lithium-ion batteries, Modeling, Multiparticle, Mechanical response, and Electrochemical
- Citation to related publication:
- Mohtat, P., Lee, S., Sulzer, V., Siegel, J. B., & Stefanopoulou, A. G. (2020). Differential Expansion and Voltage Model for Li-ion Batteries at Practical Charging Rates. Journal of The Electrochemical Society, 167(11), 110561. https://doi.org/10.1149/1945-7111/aba5d1
- Discipline:
- Engineering
-
- Creator:
- Ponder, Brandon M., Ridley, Aaron J., Goel, Ankit, and Bernstein, Dennis S.
- Description:
- 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.
- Keyword:
- Thermosphere, GITM, CHAMP, GRACE, MSIS, Upper Atmosphere Modeling, and Data Assimilation
- Citation to related publication:
- 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
- Discipline:
- Engineering and Science
-
- 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
-
- 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:
- Raghani, Ravi M, Urie, Russell R, and Shea, Lonnie D
- Description:
- 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.
- Keyword:
- Immunotherapy resistance, Biomaterials, Metastasis, Checkpoint blockade, and Therapy monitoring
- Discipline:
- Engineering and Health Sciences
-
- Creator:
- Yining Shi
- Description:
- 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.
- Discipline:
- Engineering
-
- Creator:
- Thompson, Ellen P. and Ellis, Brian R.
- Description:
- 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.
- Keyword:
- Carbonate dissolution, X-ray computed tomography, Porous media, Topology, and Persistent homology
- Citation to related publication:
- Thompson, E.P.; Ellis, B.R. (2023) Persistent Homology as a Heterogeneity Metric for Predicting Pore Size Change in Dissolving Carbonates. In Review.
- Discipline:
- Science and Engineering