DataScienceCoursera-GCD

================================================================== Getting and Cleaning Data Course Project Version 1.0

John Jay zj05409@qq.com

The background

This project is my answer to the course project at https://www.coursera.org/learn/data-cleaning/peer/FIZtT/getting-and-cleaning-data-course-project

The dataset includes the following files:

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'README.txt'
'run_analysis.R': a script which merges and cleans the original data sets.

The script do the following:

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merges the test, training, subjects and activities data sets from [1] http://archive.ics.uci.edu/ml/datasets/Human+Activity+Recognition+Using+Smartphones
extract the mean and std columns,
modifies the names of the columns,
change the activity column from number to the corresponding labels.

After running this script, you will get a file named "ucihardata.txt", which contain a tidy data set.

Code Book

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The resulting dataset contains the following columns:

"subject" is the person id
"activity" is the type of the actions taken by the person, with the following values: WALKING, WALKING_UPSTAIRS, WALKING_DOWNSTAIRS, SITTING, STANDING, LAYING
"tBodyAccMean-X","tBodyAccMean-Y","tBodyAccMean-Z" Mean value of triaxial body acceleration raw data
"tBodyAccStd-X","tBodyAccStd-Y","tBodyAccStd-Z" Standard deviation value of triaxial body acceleration raw data
"tGravityAccMean-X","tGravityAccMean-Y","tGravityAccMean-Z" Mean value of triaxial gravity acceleration raw data
"tGravityAccStd-X","tGravityAccStd-Y","tGravityAccStd-Z" Standard deviation value of triaxial gravity acceleration raw data
"tBodyAccJerkMean-X","tBodyAccJerkMean-Y","tBodyAccJerkMean-Z" Mean value of triaxial body linear acceleration
"tBodyAccJerkStd-X","tBodyAccJerkStd-Y","tBodyAccJerkStd-Z" Standard deviation value of triaxial body linear acceleration
"tBodyGyroMean-X","tBodyGyroMean-Y","tBodyGyroMean-Z" Mean value of triaxial body angular velocity raw data
"tBodyGyroStd-X","tBodyGyroStd-Y","tBodyGyroStd-Z" Standard deviation value of triaxial body angular velocity raw data
"tBodyGyroJerkMean-X","tBodyGyroJerkMean-Y","tBodyGyroJerkMean-Z" Mean value of triaxial body linear angular velocity
"tBodyGyroJerkStd-X","tBodyGyroJerkStd-Y","tBodyGyroJerkStd-Z" Standard deviation value of triaxial body linear angular velocity
"tBodyAccMagMean" Mean value of body acceleration raw data magnitude
"tBodyAccMagStd" Standard deviation value of body acceleration raw data magnitude
"tGravityAccMagMean" Mean value of gravity acceleration raw data magnitude
"tGravityAccMagStd" Standard deviation of gravity acceleration raw data magnitude
"tBodyAccJerkMagMean" Mean value of body linear acceleration magnitude
"tBodyAccJerkMagStd" Standard deviation value of body linear acceleration magnitude
"tBodyGyroMagMean" Mean value of body angular velocity raw data magnitude
"tBodyGyroMagStd" Standard deviation value of body angular velocity raw data magnitude
"tBodyGyroJerkMagMean" Mean value of body linear angular velocity magnitude
"tBodyGyroJerkMagStd" Standard deviation value of body linear angular velocity magnitude
"fBodyAccMean-X","fBodyAccMean-Y","fBodyAccMean-Z" FFT of "tBodyAccMean-X","tBodyAccMean-Y","tBodyAccMean-Z"
"fBodyAccStd-X","fBodyAccStd-Y","fBodyAccStd-Z" FFT of
"fBodyAccJerkMean-X","fBodyAccJerkMean-Y","fBodyAccJerkMean-Z" FFT of "tBodyAccJerkMean-X","tBodyAccJerkMean-Y","tBodyAccJerkMean-Z"
"fBodyAccJerkStd-X","fBodyAccJerkStd-Y","fBodyAccJerkStd-Z" FFT of "tBodyAccJerkStd-X","tBodyAccJerkStd-Y","tBodyAccJerkStd-Z"
"fBodyGyroMean-X","fBodyGyroMean-Y","fBodyGyroMean-Z" FFT of "tBodyGyroMean-X","tBodyGyroMean-Y","tBodyGyroMean-Z"
"fBodyGyroStd-X","fBodyGyroStd-Y","fBodyGyroStd-Z" FFT of "tBodyGyroStd-X","tBodyGyroStd-Y","tBodyGyroStd-Z"
"fBodyAccMagMean" FFT of "tBodyAccMagMean"
"fBodyAccMagStd" FFT of "tBodyAccMagStd"
"fBodyBodyAccJerkMagMean" FFT of "tBodyBodyAccJerkMagMean"
"fBodyBodyAccJerkMagStd" FFT of "tBodyBodyAccJerkMagStd"
"fBodyBodyGyroMagMean" FFT of "tBodyBodyGyroMagMean"
"fBodyBodyGyroMagStd" FFT of "tBodyBodyGyroMagStd"
"fBodyBodyGyroJerkMagMean" FFT of "tBodyBodyGyroJerkMagMean"
"fBodyBodyGyroJerkMagStd" FFT of "tBodyBodyGyroJerkMagStd"

Notes:

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To run the script, you should first download the dataset from https://d396qusza40orc.cloudfront.net/getdata%2Fprojectfiles%2FUCI%20HAR%20Dataset.zip and unzip it in the same folder as the script.

References:

======== [1] 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

John Jay. September 2016.

zj05409/DataScienceCoursera-GCD