Search results

RSS feed for this result

1,156 results

Collection
Stanford Research Data
The data and code provided here are supplementary information for the paper “Incoherence of Partial Component Sampling in multidimensional NMR" by H. Monajemi, D.L. Donoho, J.C. Hoch, and A.D. Schuyler. Please read INSTRUCTION.TXT for reproducing the results of the article. Abstract of the article: In NMR spectroscopy, random undersampling in the indirect dimensions causes reconstruction artifacts whose size can be bounded using the so-called {\it coherence}. In experiments with multiple indirect dimensions, new undersampling approaches were recently proposed: random phase detection (RPD) \cite{Maciejewski11} and its generalization, partial component sampling (PCS) \cite{Schuyler13}. The new approaches are fully aware of the fact that high-dimensional experiments generate hypercomplex-valued free induction decays; they randomly acquire only certain low-dimensional components of each high-dimensional hypercomplex entry. We provide a classification of various hypercomplex-aware undersampling schemes, and define a hypercomplex-aware coherence appropriate for such undersampling schemes; we then use it to quantify undersampling artifacts of RPD and various PCS schemes.
Collection
Stanford Research Data
The Fundamental Kinetic Database Utilizing Shock Tube Measurements Database summarizes the published shock tube experimental work performed under the supervision of Prof. Ronald K. Hanson of the Mechanical Engineering Department at Stanford University. The database covers the years from 1974 to 2013 inclusively. The database is divided into three types of data: ignition delay times, species time-history measurements, and reaction rate measurements. Volumes are in DOCX format and data tables in the volumes can be easily cut and pasted into separate user spread sheets. Volume 1 of the Fundamental Kinetic Database Utilizing Shock Tube Measurements includes a summary of the ignition delay time data measured and published by the Shock Tube Group in the Mechanical Engineering Department of Stanford University. The cut-off date for inclusion into this volume was January 2005. Volume 2 includes a summary of the species concentration time-histories. The cut-off date for inclusion in this volume was December 2005. Some of the figures embedded in this DOCX file can be opened using ORIGIN software. The data in this volume is available in tabular form in the accompanying ZIP file or in this volume. Volume 3 includes a summary of the reaction rate measurements. The cut-off date for inclusion in this volume was January 2009. Volume 4 includes a summary of the ignition delay time data. The start data for inclusion into this volume is January 2005 (the cutoff date for Volume 1) and the cutoff date is January 2014. Volume 5 includes a summary of the species concentration time-histories. The cut-off date for inclusion in this volume was January 2014. The format of this volume differs from that of Volume 2 in that we have not included the data files. Some of this data is available in the relevant papers and some of the data files may be accessible by contacting Dr. David Davidson at dfd@stanford.edu. Much of this data was used for reaction rate constant determinations and the mixtures in the experiments reflect this use; the mixtures were designed to isolate or enhance the sensitivity of the measured species to a particular reaction rate constant. Volume 6 includes a summary of the reaction rate measurements. The cut-off date for inclusion in this volume was January 2014.
Collection
Stanford Research Data
The Mapping Interstate Territorial Conflict (MITC) project consists of precise digital maps of regions that were the subject of interstate territorial disputes in the period 1947-2000. Disputes identified by Huth and Allee (2002) were rendered as polygons corresponding the regions of states' overlapping claims. This deposit contains a link to the shapefile containing these polygons as well as several data sets derived from this shapefile. Further information can be found in the codebook and the published paper describing these data, referenced below.
Collection
Stanford Research Data
Of all the activity observed on the Sun, two of the most energetic events are flares and Coronal Mass Ejections (CMEs). Usually, solar active regions that produce large flares will also produce a CME, but this is not always true (Yashiro et al., 2005). Despite advances in numerical modeling, it is still unclear which circumstances will produce a CME (Webb & Howard, 2012). Therefore, it is worthwhile to empirically determine which features distinguish flares associated with CMEs from flares that are not. At this time, no extensive study has used physically meaningful features of active regions to distinguish between these two populations. As such, we attempt to do so by using features derived from [1] photospheric vector magnetic field data taken by the Solar Dynamics Observatory's Helioseismic and Magnetic Imager instrument and [2] X-ray flux data from the Geostationary Operational Environmental Satellite's X-ray Flux instrument. We build a catalog of active regions that either produced both a flare and a CME (the positive class) or simply a flare (the negative class). We then use machine-learning algorithms to [1] determine which features distinguish these two populations, and [2] forecast whether an active region that produces an M- or X-class flare will also produce a CME. We compute the True Skill Statistic, a forecast verification metric, and find that it is a relatively high value of 0.8 plus or minus 0.2. We conclude that a combination of six parameters, which are all intensive in nature, will capture most of the relevant information contained in the photospheric magnetic field. The code and data used to do this analysis are included here.
Collection
Stanford Research Data
Marine mammals play crucial ecological roles in the oceans, but little is known about their microbiotas. Here we study the bacterial communities in 337 samples from 5 body sites in 48 healthy dolphins and 18 healthy sea lions, as well as those of adjacent seawater and other hosts. The bacterial taxonomic compositions are distinct from those of other mammals, dietary fish and seawater, are highly diverse and vary according to body site and host species. Dolphins harbour 30 bacterial phyla, with 25 of them in the mouth, several abundant but poorly characterized Tenericutes species in gastric fluid and a surprisingly paucity of Bacteroidetes in distal gut. About 70% of near-full length bacterial 16S ribosomal RNA sequences from dolphins are unique. Host habitat, diet and phylogeny all contribute to variation in marine mammal distal gut microbiota composition. Our findings help elucidate the factors structuring marine mammal microbiotas and may enhance monitoring of marine mammal health.
Collection
Stanford Research Data
Background: Stereotactic laser ablation and neurostimulator placement represent an evolution in staged surgical intervention for epilepsy. As practice evolves, optimal targeting will require standardized outcome measures that compare electrode lead or laser source with post-procedural changes in seizure frequency. Since non-lesional seizure foci are localized to the hippocampus by semiology and electrophysiology, stereotactic indirect targeting may be required for optimal targeting and outcome. We propose and present a novel stereotactic coordinate system based upon mesial temporal anatomic landmarks to facilitate the planning and delineation of outcomes based on extent of ablation of mesial temporal structures. Methodology: The body of the hippocampus contains a natural axis, approximated by the interface of CA4 and the dentate gyrus. The uncal recess of the lateral ventricle acts as a landmark to characterize anterior-posterior extent. Several volumetric rotations are quantified for alignment with the hippocampal coordinate system. First, the brain volume is rotated to align with standard AC-PC space. Then, it is rotated through the angles the hippocampal-axis makes with the AC/PC-line, from both an axial and sagittal view. Results: Using this coordinate system, customized MATLAB software was developed to allow for intuitive standardization of targeting and interpretation. The angle between the AC/PC-line and the hippocampal-axis was found to be ~20-30° when viewed sagittally and of order ~0-10° when viewed axially. Implanted electrodes can then be identified from CT in this space, and laser tip position and burn geometry can be calculated based on the intraoperative and post-operative MRI. Conclusion: With the advent of stereotactic surgery for mesial temporal targets, a hippocampal stereotactic system is introduced which may facilitate operative planning, improve surgical outcomes, and standardize outcome assessment.
Collection
A tide prediction and tide height control system for laboratory mesocosms
This archive contains materials related to a tide prediction system and laboratory aquarium tide height control system. It includes a set of tide prediction libraries meant to run on Arduino microcontrollers. The libraries are based on data generated by the National Ocean and Atmospheric Administration's National Ocean Service, and were compiled by David Flater for the open source program XTide. The data from XTide were then adapted to generate the individual libraries for a variety of sites around the US mainland, Alaska, Hawaii, Puerto Rico and the Virgin Islands. We also provide a set of R scripts to generate new libraries for additional NOAA tide station sites that are not included in this repository. See the folder "Generate_new_site_libraries" in the archive for the scripts and description of the library generation process. Diagrams and parts lists for the mechanical portion of the tide control rack are provided as well. R code and raw data for the plant growth analysis are provided as well.
Collection
Stanford Center for Reservoir Forecasting (SCRF)
The SCRF Benchmark Reservoir is a synthetic fractured reservoir created by using Paradigm SKUA 2013.2 version. This synthetic dataset is intended to serve as a test bed for algorithms and workflows aimed at prediction of subsurface geology, reservoir modeling and forecasting in fractured reservoirs. The Benchmark reservoir has a three-layered subsurface geology reflecting aeolian, fluvial and coastal environments and major sealing faults that dissect the domain into a “core”, “graben” and a “horst” area. It is populated with relevant facies properties, porosity and permeability. Fracture intensity and orientation distributions are computed from geomechanical constraints. The influence of these fractures on elastic properties and seismic responses is evaluated based on computation of the effective elastic stiffness tensor. Workflows and details of models used in generating the Benchmark Reservoir are documented under "Major Workflows and Models" as data_generation.docx The data set is an appendix to the following manuscript to be submitted to Computers and Geosciences that can be found as a pdf file under "Associated Manuscript Draft1": Roy, A., Shin, Y, Li, P., Aydin, O., Jung, A., Mukerji, T and Caers, J., "A Benchmark Dataset for Fractured Reservoirs" There are three files in this data set: 1) BM_ReservoirModel.sprj is the Benchmark SKUA project user interface 2) BM_REservoirModel.prj.7z is zip file containing the Benchmark SKUA project folder 3) BM_Properties.7z is a zip file containing data files on properties, faults and horizons from the Geologic Grid (1) and (2) can be accessed and opened in SKUA: Please download and unzip (2) before opening the project. The SKUA project contains: wells, structural model (faults and horizons), geologic properties (e.g. facies), petrophysical properties, fracture intensity and orientation, seismic attributes (e.g. velocities) and a reference DFN (not part of the main Benchmark) There are two grids in the project: a) Geologic Model: contains the faices models, petrophysical properties, elastic properties and seismic attributes. b) Flow Model: covers part of the area modeled by (a). Smaller and coarser grid containing the DFN. Also, relevant properties (e.g. fracture intensity, orientation) are copied from (a). Flow responses are simulated in this grid
Collection
Stanford Geospatial Center Teaching Data
This shapefile was created from the Clowns of America, International Membership Database (anonymized) obtained in 2007 from Clowns of America, International, for use in teaching. It was created by geocoding the ZipCode field of the original table, using OpenRefine and the Geonames.org PostalCodes API. Attributes include those from the original data table ('City', 'ZipCode', 'Clown_Name', and 'Country'), as well attributes added during the geocoding process ('admname1','adm1','adm2','placname','longitude','latitude') and an attribute 'Clown-Na_1' which represents the values in the 'Clown_Name' attribute field after a "Cluster and Edit" operation, performed in OpenRefine to collapse values so that "Co Co" or "Co-Co" both are clustered and edited to become "CoCo" for use in name frequency analysis.
Collection
Software and data produced by Baker Research Group
This page provides data and code to document the referenced paper, which examines four methods by which ground motions can be selected for dynamic seismic response analyses of engineered systems when the underlying seismic hazard is quantified via ground motion simulation rather than empirical ground motion prediction equations. Even with simulation-based seismic hazard, a ground motion selection process is still required in order to extract a small number of time series from the much larger set developed as part of the hazard calculation. Four specific methods are presented for ground motion selection from simulation-based seismic hazard analyses. One of the four methods provides a ‘benchmark’ result (i.e. using all simulated ground motions), enabling the consistency of the other three more efficient selection methods to be addressed.
Collection
Stanford Research Data
Included in this supplement to Lau et al. (2016) is the R code used to explore controls on d238U and [U] in seawater (U model.R) (Figures 1 and S6). We also include the R code used to explore the links between the OMZ and the carbon cycle (Figures 4, S8). We make this code available without restriction for any purpose as long as the original paper is properly cited.
Collection
Stanford Research Data
Included in this supplement is the R code used to calculate Pliocene changes in EAIS mass and global sea level as function of temperature change based on the LR04 benthic stack using Eq.'s 1 and 2 of Winnick and Caves (2015). We make this code available without restriction for any purpose as long as the original paper is properly cited.

13. CoreLogic tax and deed data [2015] Online

Dataset
1 online resource (6 data files) Digital: data file.
This data set contains two sets of data, nationwide tax and deed data for all counties in the United States, approximately 145 million properties, residential and commerical. Data are collected from U.S. County Assessor and Recorder offices, cleaned and normalized by CoreLogic.
Collection
Stanford Research Data
The mechanisms of perceptual decision-making are frequently studied through measurements of reaction time (RT). Classical sequential-sampling models (SSMs) of decision-making posit RT as the sum of non-overlapping sensory, evidence accumulation, and motor delays. In contrast, recent empirical evidence hints at a continuous-flow paradigm in which multiple motor plans evolve concurrently with the accumulation of sensory evidence. Here we employ a trial-to-trial reliability-based component analysis of encephalographic data acquired during a random-dot motion task to directly image continuous flow in the human brain. We identify three topographically distinct neural sources whose dynamics exhibit contemporaneous ramping to time-of-response, with the rate and duration of ramping discriminating fast and slow responses. Only one of these sources, a parietal component, exhibits dependence on strength-of-evidence. The remaining two components possess topographies consistent with origins in the motor system, and their covariation with RT overlaps in time with the evidence accumulation process. After fitting the behavioral data to a popular SSM, we find that the model decision variable is more closely matched to the combined activity of the three components than to their individual activity. Our results emphasize the role of motor variability in shaping RT distributions on perceptual decision tasks, suggesting that physiologically plausible computational accounts of perceptual decision-making must model the concurrent nature of evidence accumulation and motor planning.
Collection
Stanford Research Data
The data package contains 10 anonymized datasets of scalp-recorded EEG in MATLAB (.mat) format. Each .mat file contains EEG data from one experimental subject. Data matrices have been preprocessed and are in the form used as input for classification. Dimensionality reduction/PCA has not been performed.
Collection
VISTA Lab
This site houses sample data and code for the publication, Takemura, H., Caiafa, C. F., Wandell, B. A., and Pestilli, F. Ensemble tractography (under review). All code in this repository is written in MATLAB (Mathworks) and, together with the included data, can be used to reproduce several of the figures from the publication. Code and data are provided as part of the goal of ensuring that computational methods are reproducible by other researchers. Note: This version of the repository is still under progress, and does not include the LiFE and ET code in the newest release. We are also preparing the GitHub repository for hosting the updated version of the script for reproducing the figure on this paper. Github repository (still under private, but will be available for public upon the publication) https://github.com/vistalab/EnsembleTractography
Collection
Stanford Research Data
Comparison of magnetic characteristics of three major active regions before and after major flare.
Database topics
Statistical and Numeric Data; Government Information: International and Foreign
Dataset
1 online resource. Digital: data file.
A single downloadable .csv file provides estimates on "violent deaths" from 2004 onwards. The violent deaths indicator combines national level statistics on homicide and data on fatalities occurred in armed conflict. The database covers more than 189 countries and territories and it is kept constantly updated. Estimates on violent deaths between 2007 and 2012 are at the core of the analysis presented in the third and latest edition of the Global Burden of Armed Violence, launched in May 2015. The database combines data from a wide range of sources that report the number of people died in violent events across both conflict and non-conflict settings. Typical sources are, among others, hospitals, mortuaries, police as well as those organizations that document casualties in areas affected by armed conflict.
Database topics
Government Information: State and Local; Statistical and Numeric Data
Dataset
1 online resource.
Collection
Software and data produced by Baker Research Group
We identify potential data sources for fling-step and discuss their value, compile a dataset of simulated and recorded ground motions containing fling, extract fling pulses from these ground motions, and derive a predictive model for fling amplitude and period that is compared to existing empirical models. Fling is the result of permanent static offset of the ground during an earthquake, but is usually ignored because ground motion records from accelerometers contain errors that make it difficult to measure static offsets. However, some data sources include fling, such as specially processed recordings, ground motion simulations, and high-rate global positioning systems (GPS). From this data, we extract fling pulses using the pattern search global optimization algorithm. The resulting displacement amplitudes and periods are used to create a new predictive equation for fling parameters, are compared to existing empirical models for pulse period, fling amplitude, and surface displacement along the fault, and are found to match reasonably well.