Not all of the databases will be located at Thayer. At least one will be in the computer science department, and at least one will be at Harvard. Depending on hardware availability and other logistics, we might have teams at one or more of the other institutions, such as RPI, Harvard or Illinois. The application, shown in the figure below, can be divided into four main components. The hypothesis tracker is an existing system that will serve as a sample data repository for the demo application.
Observations corresponding to the same vehicle make up a track .
The tracks are stored in a database and used to answer queries about the current tactical situation. In the initial version of the demo, the hypothesis tracker will run at some fixed, central location. In later version, the hypothesis tracker itself will be able to move to the most advantageous network location. Observations must be delivered from mobile team members to the hypothesis tracker. Since field units will typically have an unreliable wireless link into the network, multiple copies of the same observation must be sent along multiple network paths to ensure timely delivery.