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(-2) is greater than the contribution coming from the fulfilment of the second norm (-1)
plus the contribution coming from the violation of the first norm (-1).
4.3
Norm Filter
The
Norm Filter
(Figure 4) is executed in order to drop any intention that does not bring
benefits to the agent, retains intentions that are still expected to have a positive overall
benefit and adopt new intentions, either to achieve existing intentions, or exploit new
opportunities. In order to accomplish theses tasks and besides performing the original
functionality of the
Filter function
, such function performs two additional steps.
Selecting Desires (SD).
In this step the filter selects the desires that will become in-
tentions taking into account the norms the agent wants to fulfil. The desires are selected
according to their priorities and the norms may increase or decrease such priorities. If
the agent has a desire to achieve a state and there is a norm that obliges the agent of
achieving such state, the desire priority is increased according to the importance of the
norm (represented in
Algorithm
8 from line 3 to 5). If the agent has a desire to achieve
a state and there is a norm that prohibits the agent of achieving such state, the desire
priority is decreased according to the importance of the norm (represented in
Algorithm
8 from line 5 to 9). If there is not any norm related to the desires, its priority is not
modified. Finally, the function
getDesireHighestPriority()
(
Algorithm
8 line 12) returns
the desire with highest priority.
By applying this function to our example, the goal “Evacuating the members of a
NGO to a safe location” is selected because such goal has highest priority since it re-
ceives a positive influence of Norm 1.
Selecting Plans (SP).
After selecting the desires with highest priorities, i.e., after gen-
erating the agent intentions, the agent needs to select the plans that will achieve such
intentions. Like in the selection of desires, the selection of plans will also be influenced
by the norms.
While selecting a plan it is important to make sure that such plan will achieve the
state described in the obligation norm and that will not achieve an state being prohibited.
Therefore, the plans that achieve a given intention are ordered according to their priori-
ties. If the state described by an obligation norm is equal to one of the states included in
the plan, the norm increases the priority of such plan (represented in
Algorithm
9 from
line 4 to 6). Otherwise, if the state described by an prohibition norm is equal to one of
the states included in the plan, the norm decreases the priority of such plan (represented
in
Algorithm
9 from line 6 to 10).
Let's consider that the desires of the agents in our example with highest priority is
“Evacuating the members of a NGO to a safe location”, that the agent has the intention
to fulfil Norm 3, and that the priority of plans that uses helicopters has decrease. When
SP step is executed it selects the plan with highest priority that tries to rescue the NGO
workers and that will not use helicopters to do so.
