Data: The data used were taken from a study of 30 volunteers aged 19-48 years. These wore a Samsung Galaxy S II smartphone while performing various activities, and the data from the phone's gyroscope and accelerometer were collected and assigned to the specific subject and activity. The data comes from the following study:
Davide Anguita, Alessandro Ghio, Luca Oneto, Xavier Parra and Jorge L. Reyes-Ortiz. Human Activity Recognition on Smartphones using a Multiclass Hardware-Friendly Support Vector Machine. International Workshop of Ambient Assisted Living (IWAAL 2012). Vitoria-Gasteiz, Spain. Dec 2012
Transformations/Analysis: The code in this analysis selects out only the mean and standard deviation variables from the data, includes information about the activity performed and the subject performing the activity for each observation, and combines data that were separated into "test" and "training" sets into one set. (70% of subjects had been assigned to "training" and the rest to "test".)
Then from this combined data set, the mean values for each variable for each subject for each activity are extracted and placed in a new data set.
Variables: The phone signals were separated into three dimensions (X, Y, and Z) and signals from bodily motion were separated from gravity-induced signals. Angular velocity and magnitude of motions were calculated as separate variables. Also, Fast Fourier Transform was applied to derive other variables from some of the signals. For each signal, variables indicate average, standard deviation, maximum, minimum, etc, but only average and standard deviation were used in this analysis.
Variable names: subject: ID number of the subject performing the activity; 1 to 30
activity: One of six activities being performed while wearing the smartphone; walking, sitting, lying, standing, walking up stairs, walking down stairs
timebodyaccelerometermeanxaxis: Average measurement from accelerometer reading of body signal on the X axis
timebodyaccelerometermeanyaxis: Average measurement from accelerometer reading of body signal on the Y axis
timebodyaccelerometermeanzaxis: Average measurement from accelerometer reading of body signal on the Z axis
timebodyaccelerometerstdxaxis: Standard deviation of measurement from accelerometer reading of body signal on the X axis
timebodyaccelerometerstdyaxis: Standard deviation of measurement from accelerometer reading of body signal on the Y axis
timebodyaccelerometerstdzaxis: Standard deviation of measurement from accelerometer reading of body signal on the Z axis
timegravityaccelerometermeanxaxis: Average measurement from accelerometer reading of gravity signal on the X axis
timegravityaccelerometermeanyaxis: Average measurement from accelerometer reading of gravity signal on the Y axis
timegravityaccelerometermeanzaxis: Average measurement from accelerometer reading of gravity signal on the Z axis
timegravityaccelerometerstdxaxis: Standard deviation of measurement from accelerometer reading of gravity signal on the X axis
timegravityaccelerometerstdyaxis: Standard deviation of measurement from accelerometer reading of gravity signal on the Y axis
timegravityaccelerometerstdzaxis: Standard deviation of measurement from accelerometer reading of gravity signal on the Z axis
timebodyaccelerometerjerkmeanxaxis: Average angular velocity measurement from accelerometer reading of body signal on the X axis
timebodyaccelerometerjerkmeanyaxis: Average angular velocity measurement from accelerometer reading of body signal on the Y axis
timebodyaccelerometerjerkmeanzaxis: Average angular velocity measurement from accelerometer reading of body signal on the Z axis
timebodyaccelerometerjerkstdxaxis: Standard deviation of the angular velocity measurement from accelerometer reading of body signal on the X axis
timebodyaccelerometerjerkstdyaxis: Standard deviation of the angular velocity measurement from accelerometer reading of body signal on the Y axis
timebodyaccelerometerjerkstdzaxis: Standard deviation of the angular velocity measurement from accelerometer reading of body signal on the Z axis
timebodygyroscopemeanxaxis: Average measurement from gyroscope reading of body signal on the X axis
timebodygyroscopemeanyaxis: Average measurement from gyroscope reading of body signal on the Y axis
timebodygyroscopemeanzaxis: Average measurement from gyroscope reading of body signal on the Z axis
timebodygyroscopestdxaxis: Standard deviation of measurement from gyroscope reading of body signal on the X axis
timebodygyroscopestdyaxis: Standard deviation of measurement from gyroscope reading of body signal on the Y axis
timebodygyroscopestdzaxis: Standard deviation of measurement from gyroscope reading of body signal on the Z axis
timebodygyroscopejerkmeanxaxis: Average angular velocity measurement from gyroscope reading of body signal on the X axis
timebodygyroscopejerkmeanyaxis: Average angular velocity measurement from gyroscope reading of body signal on the Y axis
timebodygyroscopejerkmeanzaxis: Average angular velocity measurement from gyroscope reading of body signal on the Z axis
timebodygyroscopejerkstdxaxis: Standard deviation of the angular velocity measurement from gyroscope reading of body signal on the X axis
timebodygyroscopejerkstdyaxis: Standard deviation of the angular velocity measurement from gyroscope reading of body signal on the Y axis
timebodygyroscopejerkstdzaxis: Standard deviation of the angular velocity measurement from gyroscope reading of body signal on the Z axis
timebodyaccelerometermagnitudemean: Average magnitude of accelerometer measurements reading the body signal
timebodyaccelerometermagnitudestd: Standard deviation of magnitude measurement from accelerometer reading the body signal
timegravityaccelerometermagnitudemean: Average magnitude of accelerometer measurements reading the gravity signal
timegravityaccelerometermagnitudestd: Standard deviation of magnitude measurement from accelerometer reading the gravity signal
timebodyaccelerometerjerkmagnitudemean: Average magnitude of accelerometer measurements of angular velocity reading the body signal
timebodyaccelerometerjerkmagnitudestd: Standard deviation of magnitude measurement of angular velocity from accelerometer reading the body signal
timebodygyroscopemagnitudemean: Average magnitude of gyroscope measurements reading the body signal
timebodygyroscopemagnitudestd: Standard deviation of magnitude measurement from gyroscope reading the body signal
timebodygyroscopejerkmagnitudemean: Average magnitude of gyroscope measurements of angular velocity reading the body signal
timebodygyroscopejerkmagnitudestd: Standard deviation of magnitude measurement of angular velocity from gyroscope reading the body signal
frequencybodyaccelerometermeanxaxis: Fourier Transform of average measurement from accelerometer reading of body signal on the X axis
frequencybodyaccelerometermeanyaxis: Fourier Transform of average measurement from accelerometer reading of body signal on the Y axis
frequencybodyaccelerometermeanzaxis: Fourier Transform of average measurement from accelerometer reading of body signal on the Z axis
frequencybodyaccelerometerstdxaxis: Fourier Transform of standard deviation of measurement from accelerometer reading of body signal on the X axis
frequencybodyaccelerometerstdyaxis: Fourier Transform of standard deviation of measurement from accelerometer reading of body signal on the Y axis
frequencybodyaccelerometerstdzaxis: Fourier Transform of standard deviation of measurement from accelerometer reading of body signal on the Z axis
frequencybodyaccelerometerjerkmeanxaxis: Fourier Transform of average angular velocity measurement from accelerometer reading of body signal on the X axis
frequencybodyaccelerometerjerkmeanyaxis: Fourier Transform of average angular velocity measurement from accelerometer reading of body signal on the Y axis
frequencybodyaccelerometerjerkmeanzaxis: Fourier Transform of average angular velocity measurement from accelerometer reading of body signal on the Z axis
frequencybodyaccelerometerjerkstdxaxis: Fourier Transform of standard deviation of the angular velocity measurement from accelerometer reading of body signal on the X axis
frequencybodyaccelerometerjerkstdyaxis: Fourier Transform of standard deviation of the angular velocity measurement from accelerometer reading of body signal on the Y axis
frequencybodyaccelerometerjerkstdzaxis: Fourier Transform of standard deviation of the angular velocity measurement from accelerometer reading of body signal on the Z axis
frequencybodygyroscopemeanxaxis: Fourier Transform of average measurement from gyroscope reading of body signal on the X axis
frequencybodygyroscopemeanyaxis: Fourier Transform of average measurement from gyroscope reading of body signal on the Y axis
frequencybodygyroscopemeanzaxis: Fourier Transform of average measurement from gyroscope reading of body signal on the Z axis
frequencybodygyroscopestdxaxis: Fourier Transform of standard deviation of measurement from gyroscope reading of body signal on the X axis
frequencybodygyroscopestdyaxis: Fourier Transform of standard deviation of measurement from gyroscope reading of body signal on the Y axis
frequencybodygyroscopestdzaxis: Fourier Transform of standard deviation of measurement from gyroscope reading of body signal on the Z axis
frequencybodyaccelerometermagnitudemean: Fourier Transform of average magnitude of accelerometer measurements reading the body signal
frequencybodyaccelerometermagnitudestd: Fourier Transform of standard deviation of magnitude measurement from accelerometer reading the body signal
frequencybodybodyaccelerometerjerkmagnitudemean: Fourier Transform of average magnitude of accelerometer measurements of angular velocity reading the body signal
frequencybodybodyaccelerometerjerkmagnitudestd: Fourier Transform of standard deviation of magnitude measurement of angular velocity from accelerometer reading the body signal
frequencybodybodygyroscopemagnitudemean: Fourier Transform of average magnitude of gyroscope measurements reading the body signal
frequencybodybodygyroscopemagnitudestd: Fourier Transform of standard deviation of magnitude measurement from gyroscope reading the body signal
frequencybodybodygyroscopejerkmagnitudemean: Fourier Transform of average magnitude of gyroscope measurements of angular velocity reading the body signal
frequencybodybodygyroscopejerkmagnitudestd: Fourier Transform of standard deviation of magnitude measurement from gyroscope reading the body signal