4 Finite State Technologies for Dialogue Processing

To finally close the topic of finite state techniques in Computational Linguistics, we will have a look at another area were they are applied with great success (in addition to morphological processing, see Section 2.3). This is the area of dialogue processing. Again we will see that finite state technology provides simple and efficient tools, but that these tools also have obvious limitations. But then, for a lot of applications simplicity and efficiency clearly make up for many limitations.

To give you some background on the topic, we will first discuss a set of general characteristics that a dialogue system should exhibit and give some example dialogues that illustrate why those characteristics are important. In the second part we will have a closer look at how to base dialogue systems on finite state automata (FSA). We will look at a dialogue system for a voice-operated elevator as an example.

• 4.1 Dialogue Processing
  • 4.1.1 Introduction
  • 4.1.2 General Dialogue characteristics
  • 4.1.3 General Dialogue characteristics: Examples

• 4.2 FSA-based dialogue systems
  • 4.2.1 Processing dialogue with finite state systems
  • 4.2.2 A simple FSA example
  • 4.2.3 Extending FSA
  • 4.2.4 Grounding extension
  • Grounding Extension 1
  • Grounding Extension 2
  • Grounding Extension 3
  • And what about Repair?

• 4.3 An in-depth look at the speaking elevator
  • 4.3.1 The Saarbrücken CL department's Speaking Elevator
  • 4.3.2 How does the dialogue progress?
  • 4.3.3 An additional memory
  • 4.3.4 How long does the system wait for a response?
  • 4.3.5 How does the elevator deal with unrecognised utterances or inconsistent input?
  • 4.3.6 And what happens if the elevator does understand the input?
  • 4.3.7 How is the user input confirmed?
  • 4.3.8 During the trip...
  • 4.3.9 What happens when there is ambiguous input?
  • 4.3.10 Speaking elevator reference

• 4.4 Examples of required behaviour
  • 4.4.1 Turn-taking
  • 4.4.2 Adjacency pairs and insertions
  • 4.4.3 Grounding
  • 4.4.4 Dialogue context
  • 4.4.5 Ellipsis
  • 4.4.6 Reference resolution
  • 4.4.7 Mixed initiative

• 4.5 Dialogue characteristic and extension of the elevator
  • 4.5.1 Turn-taking
  • 4.5.2 Adjacency pairs and insertions
  • 4.5.3 Grounding
  • 4.5.4 Dialogue context
  • 4.5.5 Ellipsis
  • 4.5.6 Reference resolution
  • 4.5.7 Mixed initiative

• 4.6 Summary and Outlook
  • 4.6.1 Advantages and disadvantages
  • 4.6.2 The CSLU tool
  • 4.6.3 Beyond finite state techniques

• 4.7 Exercises