Information Technology Reference
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episode composed of an event to which the protagonist reacts without forming
any goals.
once upon a time there lived a dog. one day it happened that farmer evicted
cat. when this happened, dog felt pity for the cat. in response, dog sneaked
food to the cat. farmer punished dog.
A slightly more complicated single-episode story has the protagonist adopt a
goal and carry out action(s) in pursuit of that goal. Stories with goals are more
complex because (1) the system must constrain the protagonist's actions to
those intended to achieve the goal, and (2) the system must track the effects of
these actions to determine if the goal is met.
once upon a time there lived a cossack. one day it happened that imp possessed
daughter of a boyar. when this happened, cossack felt love for the daughter of
a boyar. in response, cossack made it his goal that he would be married to the
daughter of a boyar. cossack exorcised the imp from the daughter of a boyar.
cossack was married to daughter of a boyar.
Our implementation also produces multiple-episode stories. Episodes may be
arranged in two ways: sequentially or nested. Episode nesting takes place when
the world model instantiates an action's effect to an event rather than a state.
In the tale below, the nested episode is emphasized. The action of the outer
episode(takingawalkinthewoods)doesnothaveastateasitseffect.Instead,
this action triggers an event (finding a pit) which initiates a nested episode.
once upon a time there lived a peasant. peasant was married to wife. one day it
happened that peasant quarreled with the wife. when this happened, peasant
felt distress. in response, peasant took a walk in the woods.
peasant found a pit
when he looked under the bush. when this happened, peasant desired to punish
wife. in response, peasant made it his goal that wife would be in the pit. peasant
tricked wife. wife was in the pit.
peasant lived alone.
The final example illustrates goal failure. When a character adopts a goal, it
must attempt to achieve it. The world model enumerates (1) the actions that a
character may take toward a given goal and (2) the effects these actions have.
The grammar tries to match the effects of the actions with the goal. When
it succeeds, the goal has been met. If the world model does not provide an
action having an effect that entails the goal or unifies with it, then the goal fails.
Our theory of rational intention (Goldman & Lang 1993; Lang 1997) specifies
conditions for an agent to give up a goal. The Joseph system incorporates these
conditions implicitly.
