Information Technology Reference
In-Depth Information
For selecting their messages based on their expectations, the agents have different
objectives, according to their respective roles. These are represented in:
1. An agent's utility function.
2. The selection method used by an agent.
From a customer's point of view, there are two objectives. On the one hand, a customer
strives to maximize the number of fulfilled orders to enable continuous product con-
sumption. On the other hand, this role is also responsible for the amount of messages
occurring in the MAS which depends on the number of receivers per message. In order
to ensure a low communication effort, the second objective is to minimize the num-
ber of order receivers. Thus, for calculating the selection values for each message, the
following utility function is employed.
1
utility
(
m
sent
)
=
|
·
eor
(
m
sent
)
(6)
|
rec
(
m
sent
)
In this function,
rec
(
m
sent
) denotes the set of receivers of message
m
sent
and
eor
(
m
sent
)
is the estimated order fulfillment rate, calculated as follows.
⎩
1 f
perf
(
m
j
)
=
INFORM
eor
(
m
sent
)
=
lookup
(
MEM
alter
,
m
sent
,
m
j
)
·
(7)
0 e
m
j
∈
M
As
perf
(
m
j
) indicates the performative of message
m
j
,the
eor
represents the estimated
probability of a positive answer to the given order. Hence, this utility function favors
those orders that have a small number of receivers while having a high estimated prob-
ability to be fulfilled.
Finally, a message
m
sent
is randomly chosen out of the set of all possible messages
with a probability based on its selection value. In order to be able to adjust the level of
randomness in this selection, the selection value is further modified by an exponent
γ
,
allowing for choosing from a range between completely random selection (
γ =
0) and
deterministically selecting the maximum value (
). Therefore, following Dittrich et
al. [3, sec. 2.1] again, selection is done using a probability distribution over all possible
messages
m
sent
, calculated as follows.
γ=∞
V
m
sent
m
j
∈
M
V
m
j
p
(
m
sent
)
=
(8)
From a supplier's point of view, on the other hand, the objectives are easier to represent.
A supplier is assumed to be generally interested in fulfilling an order, if possible. If it
is not possible to fulfill all orders, a supplier prefers to maximize the system's stability
in terms of predictability of further incoming orders and anticipated expectations of the
customers. In other words, a supplier favors orders by his regular customers as he can
expect them to place further orders in the future and he can anticipate the expectation
of their orders being fulfilled. This setting is directly represented in the weighted sum
of EC and AE. Thus, the supplier's utility function remains unused (
utility
(
m
sent
)
=
1).
