Extending Loosely Coupled Federated Information Systems Using Agent Technology - Distributed Artificial Intelligence, Agent Technology, and Collaborative Applications - page 125

semantic information about the agents and the localized URI (uniform resource identifier) needed to
access the OWL-S document at the data source. The OWL-S document at the EDF includes the fol-
lowing information:

• Data sources registered with the FIS

• The URI for accessing the ontology document at each individual data source

• Active IC agent addresses, locations, and templates deployed for each known data source

Data-source updates (addition, changes, deletion) at the foundation layer of the FIS are conveyed
to the EDF by the communication controller (CC) agent. The URI to access the ontology document of
the new data source is registered in the OWL-S document maintained by the EDF. As soon as a new
data source enters the FIS, the CC agent passes the URI to access the ontology document of the new
data source to the EDF, which in turn updates its own OWL-S document. This mechanism provides a
means to maintain a data-source access list that is current and in correspondence with the structure of
the foundation layer. If new data sources enter the federation that are similar to existing data sources,
then active IC agents can be deployed to interface with the new sources. If a new IC agent has to be
created or changes have to be made, all requisite information needed to implement the changes is passed
on to the extensibility management agent (EMA). It is the role of the EMA to provide the appropriate
code templates needed to create or modify the IC agents. Schema changes, if any, which may occur at
an existing data source, are also conveyed to the EDF by the CC agent by referring to the last updated
tag of the source URI. The scope of the change can then be determined by accessing the ontology docu-
ment of the data source via the URI before an IC agent is called into service. In the same manner, data
sources that are no longer valid are removed from the EDF's listing once the CC agent informs the EDF
about the deletion of the data source.

Utility in the Running Example: The loan officer requests an employment check and verification
of bank accounts and stock investments of the client. Assuming that an IC agent is already active and
deployed to query the employment information data source, all relevant data pertaining to the client will
be returned by the IC agent to the EDF. Banks that are in partnership with the loan office are already
part of the federation, and IC agents can be called into service to review the bank history of the appli-
cation. However, if the stock investment firm is newly added to the federation, the EDF can invoke the
services of the EMA to create a new IC agent that can interact with the new data source. The results
from the IC agents are assimilated by the EDF and presented to the PA. A snippet of the sample OWL
document maintained by the EDF is shown in Table 1 (Row 3).

extensibility Management Agent

The role of the EMA is to help with the actual creation or modification of the IC agents that interact
with the data sources. The EMA plays an active role under the following circumstances:

• Creation of new agents to interact with a new data source

o Instantiation of an IC agent, which maybe derivable from an existing IC type if the new data
source is similar to one that already exists
o Creation of a new IC agent by combining functions from existing agent templates