Phone Screen

Sensor parameters description for [PHONE_SCREEN]:

Key	Description
[CONTAINER]	Data stream container (database table, CSV file, etc.) where the screen data is stored. This can be a single container or an array of containers

RAPIDS provider

Available time segments and platforms

• Available for all time segments
• Available for Android and iOS

File Sequence

- data/raw/{pid}/phone_screen_raw.csv
- data/raw/{pid}/phone_screen_with_datetime.csv
- data/interim/{pid}/phone_screen_episodes.csv
- data/interim/{pid}/phone_screen_episodes_resampled.csv
- data/interim/{pid}/phone_screen_episodes_resampled_with_datetime.csv
- data/interim/{pid}/phone_screen_features/phone_screen_{language}_{provider_key}.csv
- data/processed/features/{pid}/phone_screen.csv

Parameters description for [PHONE_SCREEN][PROVIDERS][RAPIDS]:

Key	Description
[COMPUTE]	Set to True to extract PHONE_SCREEN features from the RAPIDS provider
[FEATURES]	Features to be computed, see table below
[REFERENCE_HOUR_FIRST_USE]	The reference point from which firstuseafter is to be computed, default is midnight
[IGNORE_EPISODES_SHORTER_THAN]	Ignore episodes that are shorter than this threshold (minutes). Set to 0 to disable this filter.
[IGNORE_EPISODES_LONGER_THAN]	Ignore episodes that are longer than this threshold (minutes), default is 6 hours. Set to 0 to disable this filter.
[EPISODE_TYPES]	Currently we only support unlock episodes (from when the phone is unlocked until the screen is off)

Features description for [PHONE_SCREEN][PROVIDERS][RAPIDS]:

Feature	Units	Description
sumduration	minutes	Total duration of all unlock episodes.
maxduration	minutes	Longest duration of any unlock episode.
minduration	minutes	Shortest duration of any unlock episode.
avgduration	minutes	Average duration of all unlock episodes.
stdduration	minutes	Standard deviation duration of all unlock episodes.
countepisode	episodes	Number of all unlock episodes
firstuseafter	minutes	Minutes until the first unlock episode.

Assumptions/Observations

1. In Android, lock events can happen right after an off event, after a few seconds of an off event, or never happen depending on the phone's settings, therefore, an unlock episode is defined as the time between an unlock and a off event. In iOS, on and off events do not exist, so an unlock episode is defined as the time between an unlock and a lock event.

2. Events in iOS are recorded reliably albeit some duplicated lock events within milliseconds from each other, so we only keep consecutive unlock/lock pairs. In Android you cand find multiple consecutive unlock or lock events, so we only keep consecutive unlock/off pairs. In our experiments these cases are less than 10% of the screen events collected and this happens because ACTION_SCREEN_OFF and ACTION_SCREEN_ON are sent when the device becomes non-interactive which may have nothing to do with the screen turning off. In addition to unlock/off episodes, in Android it is possible to measure the time spent on the lock screen before an unlock event as well as the total screen time (i.e. ON to OFF) but these are not implemented at the moment.

3. We transform iOS screen events to match Android’s format, we replace lock episodes with off episodes (2 with 0) in iOS. However, as mentioned above this is still computing unlock to lock episodes.