We are a research team conducting a study collecting subject's SensorKit speech data, and we've encountered some questions we couldn't resolve ourselves or by looking up the online SensorKit documentation: Microphone Activation: In general, how is the microphone being turned on to capture a speech session? And how was each session determined to be an independent session? Negative Values: In the speech classification data, there are entries where some of the start and end values are negative (see screenshot below). How should we interpret and handle these values? Is it safe to filter them out? Duplicated sessions: From the same screenshot you can see there are multiple session identifiers linked to the same subject with the same timestamp - what does this represent? Another Negative Values: The same question for speech recognition data's average pause duration, what does the -1 mean and should we remove them as well? (Note that these screenshot got rid of subject IDs for privacy purposes but each screenshot was from one subject.) We greatly appreciate your time and help.