Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Step-by-step illustration of the 2SpamH algorithm, where the size of each data point on the constructed feature space represents a daily observation of step count; (a) feature space construction with the first principal component of phone usage measures (x-axis), and the normalized number of step count uploads (y-axis); (b) prototype selection (red = “missing”, blue = “non-missing”); (c) k-nearest neighbors algorithm.
