Com S 362 
August 30 - Lecture notes addendum

Example use cases

***************************************************
  Example # 1
***************************************************

Library Administration Problem - A system is 
needed to administer a lending library. 
Membership is required to borrow books, but 
not for reading them in the library premises. 
Books may be ordered and can be obtained from 
associated libraries. Overdue books incur 
fines. Various management reports are required. 

Use Case for the Library Administration 
Machine in casual format:

Actors:
 Primary - Library member (patron), Librarian
 Secondary - Book record, other similar systems 
             at different libraries
 Offstage - US Copyright law (title 17)

Success Scenarios

#1: A patron approaches the library 
administration machine with books to borrow. The 
patron enters her/his membership information. The 
machine verifies the membership information. The 
patrons enters the book information. The machine 
updates the library catalog to reflect that the 
book is checked out. The machine outputs a receipt
containing the due date. The patron receives a receipt 
from the machine.

#2: A patron approaches the library 
administration machine with books to return. The 
patrons enters the book information. The machine 
updates the library catalog to reflect that the 
book is returned. The machine outputs a receipt
confirming that the book is returned. The patron 
receives a receipt from the machine.

Alternate Scenarios

#1: A patron approaches the library administration 
machine. The patron enters her/his membership 
information. The machine verifies the membership 
information. The machine determines that the 
patron has overdue books that are accumulating 
fines. The machine outputs this information and 
asks the patron to pay the fine. The patron decides 
to pay the fine. The machine updates patrons' record
to reflect that the fines are paid. The machine 
outputs a confirmation of the paid fines. 

#2: A patron approaches the library administration 
machine. The patron enters her/his membership 
information. The machines verifies the membership
information. The machine determines that the patrons' 
borrowing privileges have been suspended. The machine
outputs this information and asks the patron to go
see a librarian. The machine updates patrons' record 
to reflect that they have been notified.

***************************************************
  Example # 2
***************************************************

Patient Monitoring Problem - A machine for 
patient monitoring is required for the ICU 
(intensive care unit) in a hospital. Each 
patient is monitored by an analog device, 
which measures factors such as pulse, 
temperature, blood pressure, and skin 
resistance. The machine should read these 
factors on a periodic basis and record the 
factors. For each patient, medical staff also 
specifies safe ranges for each factor. If a 
factor falls outside a patient's safe range, 
or if an analog device fails, the nurses' 
station is notified. 

Use Case for the Patient-Monitoring 
Machine in casual format:

Actors:
 Primary - Patient through Pulse Reader, Patient 
    through temperature reader, Patient through
    blood pressure reader, Nurse
 Secondary - Record of safe ranges
 Offstage - FDA, Hospital Administration

Success Scenarios

#1: A nurse arrives at the nurses' station and 
specifies the safe range for the pulse rate for 
a patient to be between 18 and 300 pulses per 
minute.

#2: A patients' pulse is being monitored. The pulse 
reader measures the pulse rate to be 85 pulses 
per minute. The monitoring machine records the 
current time and pulse rate.

Alternate Scenarios

#1: The pulse reader measures the pulse rate to be 
17 pulses per minute. The monitoring machine 
notifies the nurses' station. It also records 
the current time and pulse rate.