In the ED procedures patients are categorized according to the severity level of their medical
condition. Walk-in patients are categorized as being the least emergent. Most emergent patients that
require immediate care from a physician are served first, while other patients are expected to see a
physician upon a number of visits to the ED, however, they have been witnessed to be waiting over
an hour in the waiting room. The ED provides medical service to the patients on a 24/7 basis of two
shifts. Each shift includes one main physician at examination room. The ED also contains one
observation room of 16 beds. The ED service delivery process can be represented by the following
set of core activities. These activities occur in a sequential manner; some of the steps are either
rearranged or are omitted for different patient types. Figure 1 shows general process flowchart and
patient flow through the system.