Use case name:	Medical Assistant Logs Out System
Unique use case ID	UC_17
Primary actor(s)	Medical Assistant.
Secondary actor(s)	Physician, Mammography technologist
Goal	Medical stuff has logged into system and might be in any functional page. But the “logout” feature is always available on any page. She can choose “log out” and the system goes to home page.
Preconditions:	Medical Assistant has logged into the system.
Flow of events:	1) After logged on, the system displayed the “log out” feature. 2) Medical staffs select “log out”. 3) The system moves back to home page. 4) Internally, system write the log out time to the audit record (The audit record has fields: name, identity, log in timestamp, log out timestamp, action they did(view, update, print)
Successful Post-condition:	The System moves back to home page and ready for any log in by a medical assistant.
Failed Post-condition:	Should no failure. Otherwise bug exists in the system.
Priority:	P1.
Branches:	No branch.
Source:	2^nd client meeting. It is an optional functionality.