Designing Multi-Agent Systems from Logic Specifications - Distributed Artificial Intelligence, Agent Technology, and Collaborative Applications - page 15

any agent on the same level in the tree hierarchy. For example, in order for the Maintenance Agent to
request information from the Student Information agent, it must pass the request to the Agent Control
Client, which then passes the request to the Master Control Client. The request is then sent down to the
Student Information Agent. This structure insures an Agent's autonomy by not creating inter-depen-
dencies among the Agents.
Master Control Agent: The Master Control Agent serves multiple purposes. First and foremost, it
is the entry point into the system. All user requests are filtered through this Agent and passed along to
the appropriate Control Agent to process the request. There are two methods that a request can be sent
to the system. The first, to facilitate online courses, is through a network socket used to receive requests
from a Web server into the system, and the second method is to pass commands into the system via
the command line in the form of a text file. Second, the Master Control Agent is the primary MPI IO
process; this is discussed in greater detail in the Implementing MPI in an Agent System section. Third,
the Master Control Agent receives the result of a command and passes it back to the user. Lastly, the
Master Control Agent controls the creation and deletion of the Control Agents.
Control Agent: The Control Agent manages requests to a specific information agent. With respect
to the implementation for this project, the Control Agent receives a command from the Master Control
Agent. Once the command is received, the Control Agent verifies that the command can be executed
by one of its information agents, and then passes the command to the information agent. After the com-
mand has been executed, the control agent receives the result from the Information Agent and passes
the result to the Master Control Agent. Also, the Control Agent manages the creation and deletion of
its information agents.
Maintenance Agent: For this implementation, the maintenance agent corresponds directly with func-
tions executed by an instructor. It processes requests directly relating to the management of course content
and class interactivity. In addition, the Maintenance Agent handles the messages sent by students to an
instructor and provides the ability for an instructor to send a message to a class or individual student.
The Maintenance Agent also has the ability to retrieve a student listing from the Student Information
Agent for a specific class.
Notification and Recommendation Agent: The Notification and Recommendation Agent relates
to the activities of a student. It delivers the course content to the student as well as any messages sent to
the class or from another student. In addition, the Notification and Recommendation allows a student
to send messages to the instructor or another student.
Student Information Agent: The Student Information Agent corresponds to the operations of the
university registrar. This Agent manages all of the student and class data. The Student Information Agent
allows students to be added and removed from a class, retrieve the list of students, retrieve a student's
information, and the addition and deletion of a class. This Agent has the highest level responsibility
simply because it manages the student information and any changes to a student. In the case of adding
a student, the Student Information sends the request to create a Notification and Recommendation agent
for the individual student. This operation allows the Notification and Recommendation Agent to begin
processing requests on behalf of the student and customizing class content for delivery.
The Master Control Agent and Control Agents both have the responsibility of managing the creation
and deletion of agents. This behavior insures the reliability of the system by not allowing a command
request to go unprocessed. This behavior is also handled automatically, meaning that specialized code
does not be added to additional agents to control agent creation and deletion.