TABLE OF CONTENTS The Electronic Ticket System (ETS) is a software system by which travelers can purchase a railway ticket with a smartcard when it is put into their Personal Digital Assistants (PDAs). The ticket is a virtual entity that can be created on the smartcard itself. Payment is made through a wireless connection with the computer system of the railway company, which itself is connected to the computer systems of a clearing house and a trust center. In our case study, the ETS does not authenticate travelers or conductors. We assume that they are authenticated by some other software system running on their PDAs.
The specification has the following structure.
Activities to be supported. Ticket workflow
Desired functionality.
Mission statement
Function refinement tree
Service description
Other required properties
Subject domain.
Entity model
Some rules for the subject domain
Subject domain dictionary
Desired ETS behavior.
Stimulus-response pairs
Ticket-selling scenario
Architectures.
Requirements-level architecture
Allocation of data to data stores
Physical network
The relevant composite system consists of the ETS, travelers, conductors, banks, and clearing houses. All these entities, including the ETS, must interact to realize this desired behavior. The entities in the composite system each have their own goal, but there is also a shared goal to sell and use rights to transport by the railway company. We can draw an activity diagram of the workflow of a ticket as it passes through several states when it is owned and used by...
