Battery Usage Data
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The data for every user (1-60) is stored in their respective directory,
user_(#) where # is the user id.

Format of the data
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1. Time when the data was recorded
2. Time elapsed since January 1 1970 
3. Battery capacity remaining
4. Whether the machine was on AC or not ?
5. What was the disk space available (in MB) in the user account ?
6. Whether the machine had Internet connectivity ?
7. What was the time since there was a keyboard event (idle time) in
milliseconds ?