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JulioV 2020-07-15 16:36:50 -04:00
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@ -622,11 +622,13 @@ Aware Android and iOS clients can collect location coordinates through the phone
There are two parameters associated with resampling fused location in the ``RESAMPLE_FUSED_LOCATION`` section of the ``config.yaml`` file. ``CONSECUTIVE_THRESHOLD`` (in minutes, default 30) controls the maximum gap between any two coordinate pairs to replicate the last known pair (for example, participant A's phone did not collect data between 10.30am and 10:50am and between 11:05am and 11:40am, the last known coordinate pair will be replicated during the first period but not the second, in other words, we assume that we cannot longer guarantee the participant stayed at the last known location if the phone did not sense data for more than 30 minutes). ``TIME_SINCE_VALID_LOCATION`` (in minutes, default 720 or 12 hours) the last known fused location won't be carried over longer that this threshold even if the phone was sensing data continuously (for example, participant A went home at 9pm and their phone was sensing data without gaps until 11am the next morning, the last known location will only be replicated until 9am). If you have suggestions to modify or improve this imputation, let us know.
*Barnett's et al features*
These features are based on a Pause-Flight model. A pause is defined as a mobiity trace (location pings) within a certain duration and distance (by default 300 seconds and 60 meters). A flight is any mobility trace between two pauses. Data is resampled and imputed before the features are computed. See this paper for more information: https://doi.org/10.1093/biostatistics/kxy059.
In RAPIDS we only expose two parameters for these features (timezone and accuracy). If you wish to change others you can do so in ``src/features/location_barnett/MobilityFeatures.R``
*Significant Locations*
Significant locations are determined using K-means clustering on pauses longer than 10 minutes. The number of clusters (K) is increased until no two clusters are within 400 meters from each other. After this, pauses within a certain range of a cluster (200 meters by default) will count as a visit to that significant location. This description was adapted from the Supplementary Materials of https://doi.org/10.1093/biostatistics/kxy059.