Information Technology Reference
In-Depth Information
Fig. 3.
A simple supply network depicting agent roles and relationships in the logistics domain
The parameter
1] weights the balance between EC and AE. The constant
c
f
avoids marginal differences in the weighted sum to cause overly high effects on the
message selection in order to retain an agent's ability to try out alternative messages,
i.e., to occasionally explore the possibility space [3, sec. 9.1].
Calculating
V
m
sent
for all possible message options
m
sent
∈
α∈
[0
,
M
enables an agent to
select its operations (i.e., the messages to be sent) according to its expectations which
are based on observations of its interaction with other agents. As the selection of an
operation leads to further observations, the aforementioned feedback loop is closed.
However, the method of actually choosing an operation in accordance with the calcu-
lated selection values remains to be determined. That method depends on an agent's
role in the MAS and is introduced in the next subsection.
4.2
Representing the Logistics Domain
When modeling supply network participants as autonomous agents, these agents may
have different capabilities. As shown in Figure 3, they can be classified in
primary
producers
that produce raw materials without consuming anything,
final consumers
that
only consume products, and
manufacturers
that consume materials and semi-finished
parts in order to transform them into new parts and products. Concerning the business
relationships between the entities, it is sufficient to distinguish the agents by their roles
as producers and/or consumers of certain goods (manufacturers acting both as producers
and consumers). Their respective possible relationships as
suppliers
and
customers
are
depicted by the edges between the entities in Figure 3 (with the left hand side of an edge
being attached to a supplier and its right hand side being connected to the respective
customer).
These relationships denote possible occurrences of order/delivery processes, that
form the fundamental operations of a logistics system. They are modeled using the
FIPA-REQUEST interaction protocol [6]: An order is placed by sending a REQUEST
message containing a product type and the requested amount of that good to any subset
of the possible suppliers for this product. An answer with the REFUSE or FAILURE
performative is considered a failure to deliver while an INFORM leads to the supplier
agent removing the specified amount of products from its inventory and the customer
adding it to its own one.
