Recursive Transition Networks
Allen’s Chapters 3
J&M’s Chapter 10
1
Recursive Transition Networks
2
RTN Arc Types
3
The metal can was dark blue
4
1
The 2 metal 3 can 4 was 5 dark 6 blue 7
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
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1 The 2 metal 3 can 4 was 5 dark 6 blue 7
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Augmented Transition Networks
Allen’s Chapters 4
J&M’s Chapter 20
9
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.
10
An ATN for NP
11
An ATN for S
12
1
the 2 dog 3 saw 4 Jack 5
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An ATN Grammar for Simple
Declarative Statements
14
The NP Network
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The PP Network
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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
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