1. Chapter 22 - Communication April 8, 2004

2. 22.5 – Semantic Interpretation Uses First Order Logic as the representation language Compositional Semantics –Instead of NP  Digit Digit –NP([x, y])  Digit(x) Digit(y), x and y are associated semantics –another application of DCG; definite clause grammar

3. Examples Applied to arithmetic –Figure 22.14 –Figure 22.15 Applied to English –Figure 22.16 –Figure 22.17

4. Augmentations Time and tense –use event calculus –for example, Verb( λx λy e  Loves(x,y) ^ After(Now, e)  loved Quasi-Logical Form [  a a  Agents] –Somewhere between syntax and semantics –Can represent different possibilities succinctly –Figure 22.18 Pragmatics can resolve indexicals. “We are in CS 536 today”.

5. 22.6 – Ambiguity and Disambiguation “Portable toilet bombed; police have nothing to go on” Lexical, e.g. “class” Syntactic, e.g. “The man gave the gift with a smile”. “The man saw the boy with the smile”. Semantic

6. Metonymy. One object stands for another. For example, “MSU said”. –  m, x, e [x = MSU ^ e  Announce(m) ^ After(Now, e) ^ Metonymy(m) ] Metaphor. Indirect comparison. For example, the notion that more is up.

7. Disambiguation argmax intent Likelihood ( intent | words, situation) Knowledge Sources –World Model –Mental Model –Language Model –Acoustic Model

8. 22.7 – Discourse Understanding Reference resolution. Relies on syntax, semantics and pragmatics. For example, “he”. Structure of coherent discourse. –Figure 22.21. Coherence Relations.

9. 22.8 – Grammar Induction SEQUITUR (1997) –No pair of adjacent symbols should appear more than once in the grammar –Every rule should be used at least twice –Figure 22.22