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.
Retrieved topological map with semantic information [35]. The red topological lines on the top show the connectivities between room labels, doors, and hallways. On the background, the green denotes the area of each room, the blue shows the hallways which are connecting with at least a threshold number of doors, and the red shows the unknown spaces.
