#CodeBook
##Data: #####Data was collected from the accelerometers within a Samsung Galaxy S smartphone from 30 participants while they performed 6 activities (walking, walking up stairs, walking down stairs, sitting, standing, and laying). #####Project Description (desription of how data was acquired): http://archive.ics.uci.edu/ml/datasets/Human+Activity+Recognition+Using+Smartphones #####Data was obtained here: https://d396qusza40orc.cloudfront.net/getdata%2Fprojectfiles%2FUCI%20HAR%20Dataset.zip #####Acceleration (total and body) was measured in g's (gravity of earth -> 9.80665 m/seg2). #####Gyroscope measurements were taken in rad/seg. #####The data was normalized to values ranging from -1 to 1. Therefore they are now unitless.
##Transformations:
- Training and Testing data sets were combined
- Only the measurements that represent a mean or standard deviation (not including meanFreq.) were retained
- Activity codes were converted to descriptive activity labels
- Data was averaged for each participant for each activity
- Column names were made more descriptive (removed special characters, changed t-> Time/f-> Freq, column names were converted to camelCase to improve readability, and names were updated to reflect the average transformations performed)
##Variables: Using the phones embedded accelerometer and gyroscope, readings of 3-axial linear acceleration (Acc) and 3-axial angular velocity (Gyro) at a constant rate of 50Hz were taken. The sensor acceleration signal was separated into the gravitational (Gravity) and body (Body) motion components using a Butterworth low-pass filter. Data was processed both within the time (Time) and frequency (Freq) domains.
- subjectid
- activity
- meanTimeBodyAccMagMean
- meanTimeBodyAccMagStDev
- meanTimeGravityAccMagMean
- meanTimeGravityAccMagStDev
- meanTimeBodyAccJerkMagMean
- meanTimeBodyAccJerkMagStDev
- meanTimeBodyGyroMagMean
- meanTimeBodyGyroMagStDev
- meanTimeBodyGyroJerkMagMean
- meanTimeBodyGyroJerkMagStDev
- meanFreqBodyAccMagMean
- meanFreqBodyAccMagStDev
- meanFreqBodyBodyAccJerkMagMean
- meanFreqBodyBodyAccJerkMagStDev
- meanFreqBodyBodyGyroMagMean
- meanFreqBodyBodyGyroMagStDev
- meanFreqBodyBodyGyroJerkMagMean
- meanFreqBodyBodyGyroJerkMagStDev
###In the X, Y, and Z planes
- meanTimeBodyAccMean + (X|Y|Z)
- meanTimeBodyAccStDev + (X|Y|Z)
- meanTimeGravityAccMean + (X|Y|Z)
- meanTimeGravityAccStDev + (X|Y|Z)
- meanTimeBodyAccJerkMean + (X|Y|Z)
- meanTimeBodyAccJerkStDev + (X|Y|Z)
- meanTimeBodyGyroMean + (X|Y|Z)
- meanTimeBodyGyroStDev + (X|Y|Z)
- meanTimeBodyGyroJerkMean + (X|Y|Z)
- meanTimeBodyGyroJerkStDev + (X|Y|Z)
- meanFreqBodyAccMean + (X|Y|Z)
- meanFreqBodyAccStDev + (X|Y|Z)
- meanFreqBodyAccJerkMean + (X|Y|Z)
- meanFreqBodyAccJerkStDev + (X|Y|Z)
- meanFreqBodyGyroMean + (X|Y|Z)
- meanFreqBodyGyroStDev + (X|Y|Z)