Activity recognition using accelerometer data

A computing device comprising:

• a physical housing configured to be worn by a user;
• at least one movement sensor enclosed within the physical housing;
• at least one computer processor enclosed within the physical housing;
• at least one memory enclosed within the physical housing, wherein the memory comprises instructions that, when executed by the at least one computer processor, cause the at least one computer processor to:
• in response to receiving from the movement sensor, a set of movement data based on one or more signals that correspond to movement of the user during a time window, generate at least one numerical descriptor for the time window;
• generate, based at least in part on the at least one numerical descriptor for the time window, a confidence indicator that corresponds to a preliminary activity label, wherein the preliminary activity label is indicative of movement of the user during the time window;
• in response to determining that the confidence indicator corresponding to the preliminary activity label fails to satisfy a condition, initiate a set of operations to determine a final activity label for the time window that are at least more computationally complex than a set of operations used to determine the preliminary activity label, wherein the final activity label is indicative of movement of the user during the time window;
• and
• in response to determining that the final activity label satisfies at least one criterion, generating a notification based at least in part on the final activity label.