Page 65 - Innovations in Intelligent Machines

54 P.B. Sujit et al.
a sequence of communication links through other agents. For instance,
they may be connected through a third agent A k with A j ∈N(A k )and
A k ∈N(A i ).
In the first case, since A j is within the communication range of A i ,itcan
exchange information with A j and resolve the conflict. While in the second
case, A i does not know about the existence of A j and so direct communication
is not feasible. So, the intermediate agents are important in the negotiation
process. In the negotiation scheme developed next, we will show that it is the
neighboring agents who contribute to the decision-making of agent A i .

Negotiation Scheme

Each agent A i performs the following actions during decision-making: (i) Sends/
receives proposals (ii) Processes received proposals and sends Accept/Reject
decisions to proposing agents (iii) Computes own route decision (iv) Implements
decision. All these actions happen within each negotiation cycle. This is shown
in Figure 4. Note that an agent A i that has no targets will have only the second
segment, while the agents that have targets as well as neighbouring agents will
have all the four segments of decision-making.
The different segments of the negotiation cycle are described below:
Send/receive proposals (NC1): Each agent evaluates the benefit associated
with each target. Let b i (T j ) be the expected benefit that A i gets by attacking
target T j , which is given by

b i (T j )= V j w r − S ij (19)
where, V j = value of target T j , w r = the weight given to search task over
the task of attacking a target, S ij = (time to reach the target T j by agent
A i )/(total flight time). The benefit set B i of A i consists of benefits for all the
tasks an agent has. Let T i be the set of all targets. The benefit set for agent
A i is represented as:

B i = {b i (T j ) | T j ∈T j } (20)
for which A i gets the maximum value, as
Agent A i chooses a target T S i
S i = arg max{b i (T j ) ∈B i } (21)
j

NC1 NC2 NC3 NC4
Decide action
Process Send based on
Send proposals received accept/reject accept/reject
proposals decisions decisions received
A Negotiation cycle
Fig. 4. Negotiation cycle