This codebook consist of following information
- Section A : Data Set Information
- Section B : File Information
- Section C : Variable
- Section D : Feature Information
##Section A) Data Set Information
The experiments have been carried out with a group of 30 volunteers within an age bracket of 19-48 years. Each person performed six activities (WALKING, WALKING_UPSTAIRS, WALKING_DOWNSTAIRS, SITTING, STANDING, LAYING) wearing a smartphone (Samsung Galaxy S II) on the waist.
Using its embedded accelerometer and gyroscope, the device captured 3-axial linear acceleration and 3-axial angular velocity at a constant rate of 50Hz. The experiments have been video-recorded to label the data manually. The obtained dataset has been randomly partitioned into two sets, where 70% of the volunteers was selected for generating the training data and 30% the test data.
The training data are saved in the train folder while test data are saved in the test folder
##Section B) File Information
The files are extracted from following zip.
https://d396qusza40orc.cloudfront.net/getdata%2Fprojectfiles%2FUCI%20HAR%20Dataset.zip
-
'features.txt': List of all features.
-
'activity_labels.txt': Links the class labels with their activity name.
-
'train/X_train.txt': Training set.
-
'train/y_train.txt': Training labels.
-
'test/X_test.txt': Test set.
-
'test/y_test.txt': Test labels.
-
'test/subject_test.txt': Each row identifies the test subject who performed the activity for each window sample. Its range is from 1 to 30.
-
'train/subject_train.txt': Each row identifies the train subject who performed the activity for each window sample. Its range is from 1 to 30.
Information about other (unused) file are not included.
##Section C) Variable Identifier :
[1] "activity_id" - Activity ID (1:6)
[2] "activity_name" - Activity Name c("WALKING","WALKING_UPSTAIRS","WALKING_DOWNSTAIRS","SITTING","STANDING","LAYING")
[3] "subject_id" - Participate ID (1:30)
Feature Variable :
[4] "angle(tBodyAccJerkMean),gravityMean)"
[5] "angle(tBodyAccMean,gravity)"
[6] "angle(tBodyGyroJerkMean,gravityMean)"
[7] "angle(tBodyGyroMean,gravityMean)"
[8] "angle(X,gravityMean)"
[9] "angle(Y,gravityMean)"
[10] "angle(Z,gravityMean)"
[11] "fBodyAcc-Mean-X"
[12] "fBodyAcc-Mean-Y"
[13] "fBodyAcc-Mean-Z"
[14] "fBodyAcc-MeanFreq-X"
[15] "fBodyAcc-MeanFreq-Y"
[16] "fBodyAcc-MeanFreq-Z"
[17] "fBodyAcc-Std-X"
[18] "fBodyAcc-Std-Y"
[19] "fBodyAcc-Std-Z"
[20] "fBodyAccJerk-Mean-X"
[21] "fBodyAccJerk-Mean-Y"
[22] "fBodyAccJerk-Mean-Z"
[23] "fBodyAccJerk-MeanFreq-X"
[24] "fBodyAccJerk-MeanFreq-Y"
[25] "fBodyAccJerk-MeanFreq-Z"
[26] "fBodyAccJerk-Std-X"
[27] "fBodyAccJerk-Std-Y"
[28] "fBodyAccJerk-Std-Z"
[29] "fBodyAccMag-Mean"
[30] "fBodyAccMag-MeanFreq"
[31] "fBodyAccMag-Std"
[32] "fBodyBodyAccJerkMag-Mean"
[33] "fBodyBodyAccJerkMag-MeanFreq"
[34] "fBodyBodyAccJerkMag-Std"
[35] "fBodyBodyGyroJerkMag-Mean"
[36] "fBodyBodyGyroJerkMag-MeanFreq"
[37] "fBodyBodyGyroJerkMag-Std"
[38] "fBodyBodyGyroMag-Mean"
[39] "fBodyBodyGyroMag-MeanFreq"
[40] "fBodyBodyGyroMag-Std"
[41] "fBodyGyro-Mean-X"
[42] "fBodyGyro-Mean-Y"
[43] "fBodyGyro-Mean-Z"
[44] "fBodyGyro-MeanFreq-X"
[45] "fBodyGyro-MeanFreq-Y"
[46] "fBodyGyro-MeanFreq-Z"
[47] "fBodyGyro-Std-X"
[48] "fBodyGyro-Std-Y"
[49] "fBodyGyro-Std-Z"
[50] "tBodyAcc-Mean-X"
[51] "tBodyAcc-Mean-Y"
[52] "tBodyAcc-Mean-Z"
[53] "tBodyAcc-Std-X"
[54] "tBodyAcc-Std-Y"
[55] "tBodyAcc-Std-Z"
[56] "tBodyAccJerk-Mean-X"
[57] "tBodyAccJerk-Mean-Y"
[58] "tBodyAccJerk-Mean-Z"
[59] "tBodyAccJerk-Std-X"
[60] "tBodyAccJerk-Std-Y"
[61] "tBodyAccJerk-Std-Z"
[62] "tBodyAccJerkMag-Mean"
[63] "tBodyAccJerkMag-Std"
[64] "tBodyAccMag-Mean"
[65] "tBodyAccMag-Std"
[66] "tBodyGyro-Mean-X"
[67] "tBodyGyro-Mean-Y"
[68] "tBodyGyro-Mean-Z"
[69] "tBodyGyro-Std-X"
[70] "tBodyGyro-Std-Y"
[71] "tBodyGyro-Std-Z"
[72] "tBodyGyroJerk-Mean-X"
[73] "tBodyGyroJerk-Mean-Y"
[74] "tBodyGyroJerk-Mean-Z"
[75] "tBodyGyroJerk-Std-X"
[76] "tBodyGyroJerk-Std-Y"
[77] "tBodyGyroJerk-Std-Z"
[78] "tBodyGyroJerkMag-Mean"
[79] "tBodyGyroJerkMag-Std"
[80] "tBodyGyroMag-Mean"
[81] "tBodyGyroMag-Std"
[82] "tGravityAcc-Mean-X"
[83] "tGravityAcc-Mean-Y"
[84] "tGravityAcc-Mean-Z"
[85] "tGravityAcc-Std-X"
[86] "tGravityAcc-Std-Y"
[87] "tGravityAcc-Std-Z"
[88] "tGravityAccMag-Mean"
[89] "tGravityAccMag-Std"
##Section D) Feature Information
The feature data are coming from the accelerometer and gyroscope 3-axial raw signals tAcc-XYZ and tGyro-XYZ. These time domain signals (prefix 't' to denote time) were captured at a constant rate of 50 Hz. Then they were filtered using a median filter and a 3rd order low pass Butterworth filter with a corner frequency of 20 Hz to remove noise. Similarly, the acceleration signal was then separated into body and gravity acceleration signals (tBodyAcc-XYZ and tGravityAcc-XYZ) using another low pass Butterworth filter with a corner frequency of 0.3 Hz.
Subsequently, the body linear acceleration and angular velocity were derived in time to obtain Jerk signals (tBodyAccJerk-XYZ and tBodyGyroJerk-XYZ). Also the magnitude of these three-dimensional signals were calculated using the Euclidean norm (tBodyAccMag, tGravityAccMag, tBodyAccJerkMag, tBodyGyroMag, tBodyGyroJerkMag).
Finally a Fast Fourier Transform (FFT) was applied to some of these signals producing fBodyAcc-XYZ, fBodyAccJerk-XYZ, fBodyGyro-XYZ, fBodyAccJerkMag, fBodyGyroMag, fBodyGyroJerkMag. (Note the 'f' to indicate frequency domain signals).
These signals were used to estimate variables of the feature vector for each pattern:
'-XYZ' is used to denote 3-axial signals in the X, Y and Z directions.
###Generalized Features
[1] tBodyAcc-XYZ
[2] tGravityAcc-XYZ
[3] tBodyAccJerk-XYZ
[4]tBodyGyro-XYZ
[5]tBodyGyroJerk-XYZ
[6]tBodyAccMag
[7]tGravityAccMag
[8]tBodyAccJerkMag
[9]tBodyGyroMag
[10]tBodyGyroJerkMag
[11]fBodyAcc-XYZ
[12]fBodyAccJerk-XYZ
[13]fBodyGyro-XYZ
[14]fBodyAccMag
[15]fBodyAccJerkMag
[16]fBodyGyroMag
[17]fBodyGyroJerkMag
###Estimated Variable The set of variables that were estimated from these signals are:
Mean : Mean value
Std : Standard deviation
MeanFreq: Weighted average of the frequency components to obtain a mean frequency
angle : Angle between to vectors.