Recursive Transition Networks

1. Recursive Transition Networks Allen’s Chapters 3 J&M’s Chapter 10

2. Recursive Transition Networks

3. RTN Arc Types

4. The metal can was dark blue

5. 1 The 2 metal 3 can 4 was 5 dark 6 blue 7

6. 1 The 2 metal 3 can 4 was 5 dark 6 blue 7

7. 1 The 2 metal 3 can 4 was 5 dark 6 blue 7

8. 1 The 2 metal 3 can 4 was 5 dark 6 blue 7

9. Augmented Transition Networks Allen’s Chapters 4 J&M’s Chapter 20

10. Augmented Transition Networks • An augmented transition network (ATN) is a recursive transition network that can perform tests and take actions during arc transitions. • An ATN uses a set of registers to store information. • A set of actions is defined for each arc, and the actions can look at and modify the registers. • An arc may have a test associated with it. The arc is traversed (and its action is taken) only if the test succeeds. • When a lexical arc is traversed, it is put in a special variable (*) that keeps track of the current word.

11. An ATN for NP

12. An ATN for S

13. 1 the 2 dog 3 saw 4 Jack 5

14. An ATN Grammar for Simple Declarative Statements

15. The NP Network

16. The PP Network

17. Register Presetting Register Presetting  Parameter Passing • vp:inf Mary wants to have a party. • _np_vp:inf Mary wants John to have a party. Register VFORM of VP Graph should be preset to inf