Answers to Exercise: Representing Roles in Events

Answers and explanations appear in bold below each question.

1. What is the most specific role of a rock in a "rock-falling" event?

  • #$objectMoving
  • #$primaryObjectMoving

#$primaryObjectMoving: This is the best answer.

 

  • #$objectMoving: This predicate is too general. It applies equally well to a bit of moss on the rock as to the rock itself.

 

2. What is the role of two objects touching each other in a #$Touching event?

  • #$objectsInContact
  • #$actorPartsInvolved

#$objectsInContact : This is the best answer. Unlike most role predicates, it takes three arguments, relating a situation with two things that are in contact in that situation.

  • #$actorPartsInvolved: This predicate takes only two arguments.

3. What is the role that is shared between a foot and a ball in a "kicking-a-ball" event?

  • #$objectsInContact
  • #$objectActedOn
  • #$actorPartsInvolved

#$objectsInContact : This is the best answer. At some point in the kicking event, the foot and the ball must be in contact, either directly or though a sock and/or shoe, etc.

  • #$objectActedOn: The ball, but not the foot, fits this predicate.
  • #$actorPartsInvolved: This one applies to the foot, but not the ball.

4. What are the most specific roles of New York and Dallas in the #$Translation-RoundTrip event mentioned in "Joe took a round-trip from New York to Dallas"?

  • #$toLocation
  • #$fromLocation
  • #$origin-RoundTrip
  • #$destination-RoundTrip

#$origin-RoundTrip : This predicate is best for New York. Note that New York is both the #$toLocation and the #$fromLocation in a round trip that starts and ends in New York.

  • #$toLocation: Too general for Dallas, wrong for New York.
  • #$fromLocation: Too general for New York, wrong for Dallas.
  • #$destination-RoundTrip : This predicate is best for Dallas, which is neither a #$toLocation or a #$fromLocation in the overall round-trip event, although it is the #$toLocation in the first leg and the #$fromLocation in the second leg of the trip.

5. Does this rule use appropriate roles, given the situation?

(#$implies
   (#$and
      (#$isa ?ACT #$PurposefulAction)
      (#$doneBy ?ACT ?DOER))
   (#$performedBy ?ACT ?DOER))

Answer: Yes, in fact this rule is one of the salient assertions for #$PurposefulAction.

6. Which of the following best reflects the #$Role played by Joe, given the situation?

(and
   (isa Sleeping01 #$Sleeping)
   (________ Sleeping01 Joe))
  • #$performedBy
  • #$bodilyDoer
  • #$doneBy

#$bodilyDoer: This is the best answer.

 

  • #$performedBy: This predicate is not appropriate for things you do when you are unconscious.
  • #$doneBy: Too general.

 

7. Should either the arg1 (#$performedBy) or the arg2 (#$Breathing) in this assertion be generalized? If so, how and why?

(#$interArgFormat1-2 #$performedBy #$Breathing #$SingleEntry)
*This assertion can be paraphrased "For any #$Breathing event, there is at most one entity that plays the #$performedBy role."

#$Breathing can be, and should be, generalized to #$SingleDoerAction and #$performedBy should be generalized to #$doneBy:

(#$interArgFormat1-2 #$doneBy #$SingleDoerAction #$SingleEntry)

This assertion is already in the KB. It says that any single-doer action can have at most one "doer," and entails that any breathing event can have at most one performer.

8. Someone is coerced into doing something (e.g. at gunpoint). Is this person a #$deliberateActors, a #$nonDeliberateActors or neither?

The actor is conscious, chooses to do it and has a purpose. Therefore the actor is deliberate. Note that the purpose (e.g. to save one's life) need not be that of the coercer.

9. What is the role of a violinist in a #$ClassicalMusicalPerformance?

  • #$performedBy
  • #$bodilyDoer
  • #$informationOrigin
  • #$directingAgent

#$performedBy : This is the best answer in general. Note that a single event can have more than one performer, which would be the case if the violinist in this example is part of an ensemble.

  • #$bodilyDoer: Not unless the violinist is acting non-deliberately.
  • #$informationOrigin: This is also a possible role predicate for the violinist, if some piece of information is being conveyed by the music.
  • #$directingAgent: Not unless the violinist is one of the agents that is in control of the performance.

10. What is the role of a conductor in a #$ClassicalMusicalPerformance?

  • #$performedBy
  • #$bodilyDoer
  • #$informationOrigin
  • #$directingAgent

#$directingAgent: This is the most appropriate role.

 

  • #$performedBy: This role is more appropriate for the vocalists or instrumentalists.
  • #$bodilyDoer: Not unless the conductor is acting non-deliberately.
  • #$informationOrigin : The conductor is an #$informationOrigin in the event that is the conducting the performance, but not in event that is the performance itself.