Situated Inference 

Objectives 

In natural language understanding, we often need to represent knowledge 
and information which depend on situations. The required mechanisms for 
situated inferences are summarized as follows: 

Environmental parameters 
Circumstantial rules of inference 
Making implicit parameters explicit 


Advantages of Quixote

The requirements for situated inference are naturally realized with the 
following basic mechanisms in Quixote: 

Situation as module 


Parameter set as an object term with attributes (feature structures) 


Circumstantial inference rule as a rule with modules 


Explication of hidden parameters by constraints 


Offer of circumstantial information by a conditional query 


Outline of Demonstration 

Situated inference with perspectives 
Variations in tense and aspects are considered differences in perspective 
toward the same situation. The inference system explicates the ambiguity 
of a phrase, integrating such perspectives for each lexical item that may 
still be temporally ambiguous by itself. We show the example of Japanese 
`-teiru', which can have three different meanings (progressive, resultant, 
or experience), depending on the context. 

Inference with knowledge and belief 
The same rule may infer different results, depending on hidden knowledge 
and beliefs. We analyze the following examples, where the result reflects 
each speaker's different knowledge. 

      If Bizet and Verdi are compatriots, then Bizet is Italian. 
      If Bizet and Verdi are compatriots, then Verdi is French. 



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