Class Plans for Ling 645/CMSC 723, Fall 1997

Class Plans for Ling 645/CMSC 723, Fall 1997
Introduction to Computational Linguistics

  1. September 3, 1997
  2. September 10, 1997
  3. September 17, 1997
  4. September 24, 1997
  5. October 1, 1997
  6. October 8, 1997
  7. October 15, 1997
  8. October 22, 1997
  9. Oct 29: no class, Linguistics Student Conference
  10. Nov 5, 1997
  11. Nov 12, 1997
  12. Nov 19, 1997
  13. Nov 26, 1997
  14. Dec 3, 1997
  15. Dec 10, 1997

September 3, 1997

  Introduction and administrative stuff

  What is computational linguistics?  
  Computational linguistics as science, engineering
  Levels of natural language analysis
  Assignment 0:

    Log in to your course account on one of the aITs machines
    Change your password!
    Read your e-mail
    Save an e-mail message to a file
    Send "hello!" e-mail to
    Look through course page,
    Look at CL Colloquium page,
    For those with little computing experience:
     - Take the Peer Training course on Unix, and/or
     - Run the 'learn' command from your course account and start
       working your way through "files" and "editor", and/or
     - Run the 'emacs' text editor, and go through the emacs tutorial
       (invoked via "ctl-h t")

  Reading for next week:

    Allen, Ch 1-2, and get started on Ch 3
  Assignment 1a:
     - Invoke the 'emacs' text editor
     - Run the "Eliza" program by typing "Meta-x doctor"
       (An alternative:
     - Play with the program for a while: can you get it to
       have a reasonably natural sounding dialogue for a sentence
       or two?  If so, what makes it natural?  If not, what are 
       the obstacles?  [Bring a written answer to class, 
       showing a dialogue or two you tried.]

  Assignment 1b:
     - Allen, Chapter 1: exercise 2.
     - Allen, Chapter 2: exercises 2, 4.
     [Bring written answers to class]

  Solution set

September 10, 1997

  Components in an NLP system
  A real-world example
  Finite-state automata: basics (not in Allen's book)

  Reading for next week: continue with Allen, Chapter 3

  Assignment 2:
    Part 2a: Basics of LISP
    Part 2b: Working with a DFA
    Part 2c: An NDFA for the English Auxiliary System
    Clarifications on assignment 2

    Some additional Formal language theory notes

   Partial solutions for Assignment 2

September 17, 1997

  Nondeterminism via backtracking: NDFAs
  Parsing as search using context-free grammars
  Top-down, bottom-up, and left-corner parsing 
  Chart parsing: the CKY algorithm
  Dotted rules and active edges

  Reading for next week: Allen, Chapter 4

  Assignment 3: 
    Part 3a: More basics of LISP
    Part 3b: Modifying the NDFA simulator
    Part 3c: CFG formalisms and parsing

  Solution set for Assignment 3

September 24, 1997

  Chomsky normal form; weak and strong equivalence
  Left-corner bottom-up parsing
  Dotted rules and active edges
  Chart parsing: the Earley algorithm
  Shieber's proof that natural language is not context free
  Assignment 4: More on CFG parsing

  Solution set for assignment 4

Oct 1, 1997

  Beyond CFGs
   Augmented transition networks (ATNs) as extending RTNs.
   Augmenting grammars with features
  Assignment: review for mid-term exam on Oct 8
              start playing with Allen's parser (optional)

Oct 8, 1997

  First midterm (90 minutes)

  Beyond CFGs: tree-adjoining grammar

  Reading for next week:  Allen, Appendex A.1; start Chapter 8
  Assignment 5: Using a CFG with features

Oct 15, 1997

  Beginning semantics
   Review of propositional logic and first-order logic
   Discussion of word senses

  Assignment 6:  
   Exploring word senses using WordNet

  Reading:  Continue with Allen, Chapter 8

Oct 22, 1997

   Lambda expressions and compositional semantic interpretation
   Rule-to-rule correspondence of syntax and semantics
   Event variables 
   Thematic roles
   (Selection restrictions)

   Assignment 7:  Logical form and semantic interpretation

  Solution set for assignment 7

Class Oct 29 cancelled for student conference.

Nov 5, 1997

   Going over Assignment 7: semantics and logical form
   Discussion of LF and QLF
     - Predication/argument notation vs. Davidsonian event variables
     - Syntactic ambiguity vs. semantic ambiguity: one QLF per parse
     - Subcategorized vs. non-subcategorized prepositional phrases

   Review of lambda-reduction

   Verb lexical semantics
     - The syntax/semantics relationship: diathesis alternations
     - Illustration using the dative alternation
     - Extended example from Levin book: hit, touch, cut, break
     - Sketch of decompositional verb representation: LCS
     - LCS as a language-independent representation

Nov 12, 1997

    Midterm exam

    Reading for next week:  Allen Ch 10 Sec 1 through 3.

Nov 19, 1997

    Reading for this week:  Allen Ch 10 Sec 1 through 3.

    Use of semantic and world knowledge in processing
     - Selection restrictions 
     - Constraint satisfaction
     - Use of selection restrictions in parsing
     - Semantic networks
    Assignment 8: selection restrictions and constraint satisfaction

Nov 26, 1997

    Reading for this week from Allen:
      Section 7.1-7.2
      Section 7.3 excluding Viterbi algorithm
      Section 7.5

    - Intro to corpus-based methods
    - N-gram models 
    - Probabilistic CFG
    - Noisy channel model

    Assignment 9: probabilistic models

Dec 3, 1997

      Church and Hanks (1990) 
      Hindle and Rooth (1993) 

    First half of class (bracketed indicates not covered)
     - Noisy channel/HMM for part of speech tagging
     - Evaluation issues: [training vs. test data], lower and upper bounds
     - [Probabilistic disambiguation of PP attachment]
     - [Mutual information and lexical association]

    Second half of class
     - Guest lecture on machine translation by Bonnie Dorr

    Assignment 10: statistical methods

Dec 10, 1997

    Reading: Lewis and Sparck-Jones (1996), "Natural Language Processing for 
             Information Retrieval"

    First half of class
     - Basics of information retrieval (IR)
     - Evaluation issues: recall and precision
     - Some attempts to improve IR using NLP

    Second half of class
     - Semester wrapup

Final exam is December 16
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