Ontology Arcs

1
Ontology Arcs
2
What will our annotation be used for?

• Statistical people are supposed to be able to
  train something based on our annotations and our
  texts.
• IE, QA, etc.
• What exactly will they train?
• Proposal Limited version of frame semantics
  including some Jackendoff/Levin style lexical
  semantics.

3
What are semantic roles for?Which meanings are
related?

• Sam opened the door with a key.
• The key opened the door.
• The door was opened by Sam with a key.
• Sams opening of the door with a key.
• Sam opened the door by turning the key.
• Sam bought a toy from Sue.
• Sue sold a toy to Sam.
• Sam took a bus to school.
• Sam ascended to the bus and went to school.
  (Hebrew)
• Sam riding on the bus, went to school.
  (Japanese)
• Sam sat on the bus, went to school. (Chinese)
• Sam went to school by bus.
• Sam went to school by taking a bus.

4
What are semantic roles for?Predicting deep
subject/object and other syntactic stuff

• Agent (or the thing that has the most agentive
  properties) will be subject of an active voice
  sentence in a nominative-accusative language.
• Other syntactic stuff
• Variation in case marking with agentivity.
• How the causee is expressed in a complex
  causative construction. (a or par o or ni)
• We probably dont care about this.

5
What are semantic roles for?Support some kinds
of inference.

• For a change verb (state, location), etc. After
  the action is finished, the theme is no longer at
  the source (location or state) and is at the goal
  (location or state).
• The solution turned from green to red.
• The car turned from the street into the driveway.
• For telic verbs, if the action is started and not
  finished, then the theme has not reached the
  goal.
• Sam started to walk to school, but then stopped.
  He has not reached school.
• (Started means really started, not got ready to
  start.)
• For activity verbs, if the agent starts to do the
  action and stops, the agent has done the action.
• Sam started to draw, but then he stopped. He has
  drawn.
• For telic verbs of creating, the theme doesnt
  exist until the action is finished. Then it
  exists.
• Sam built a house.

6
Pros and Cons of approaches

• Verb-specific roles
• Pro
• Once you pick the role names, there is probably
  high agreement on assigning NPs to roles.
• Identifies paraphrase relations using the same
  verb.
• Con
• You cant tell that a writer and a singer
  have anything in common. So you cant generally
  apply any inferences related to agentivity.

7
PropBank

• Combination of verb specific roles and marker of
  deep subject/object.

8
Pros and Cons

• The Jackendoff motion metaphor/localist approach
• Agent, theme, source, goal, path
• Motion, state, possession, telling, creating,
  reaching/extending, attaching
• Pros
• Identify paraphrase relations using the same
  verb.
• Support some inferences across different verbs.
• Cons
• We didnt get high intercoder agreement
• But we can improve the definitions and work on
  common confusions.
• The motion metaphor doesnt cover every verb.
  (risk death, spare his life, the car rumbled,
  identify some problems)
• At the point where the motion metaphor breaks
  down, assigning a role becomes unscientific.
• Would be better if NPs could have dual roles
  agent/theme, agent/source, etc.
• Its never clear how experiencer verbs fit in.

9
Pros and Cons

• Frame semantics
• Commercial transaction, use transportation, etc.
• Pros
• Supports paraphrase relations using the same
  verb.
• Supports paraphrase relations across verbs
  (assuming that the ontology assigns the verbs to
  the same frame)
• Once the frame is identified, there is probably
  high agreement on assigning roles.
• Cons
• Framenet gets rearranged every once in a while.
• Maybe a verb can be in more than one frame or
  maybe the frame depends on the situation
• Sam took a bus to school for one dollar.
• Transportation or commercial transaction?
• Framenet currently has multiple inheritance.
  Transportation events are types of commercial
  transactions.
• Problem of assigning roles gets turned into a
  problem of assigning frames.

10
Proposal

• For the rest of Year 1
• Try to improve the definitions and common
  confusions of the Jackendoff system.
• After Year 1
• Agentivity
• Lexical aspect? (activity, accomplishment,
  achievement, state)
• Multiple frames
• Jackendoff motion metaphor is one kind of frame
• Levin verb classes are also frames
• E.g., Emit sound (rumble), change location, etc.
• Identify some number of other frames from
  framenet that cover a lot of ground.
• Annotators are responsible for frame name
  (assuming that it changes with the context) and
  the roles.
• There can be more than one frame name and more
  than one set of roles.

11
Proposal

• Useful for IE and QA and maybe even MT.
• Funding agencies can add frames that they are
  interested in, e.g., use weapon.
• Should be ok cross-linguistically.
• By assigning multiple frames, conflations can be
  identified
• Float into the cave.
• Take the bus to school.
• Rumble down the street.
• Hammer the nail flat.