Natural Language Interface Gems

Hiyan Alshawi
David Carter
Jan van Eijk
Björn Gambäck
Robert C. Moore
Douglas B. Moran
Fernando C.N. Pereira
Stephen G. Pulman
Manny Rayner
Arnold G. Smith

CLE

1986 - 1989, Hiyan Alshawi, David Carter, Jan van Eijk, Björn Gambäck, Robert C. Moore, Douglas B. Moran, Fernando C.N. Pereira, Stephen G. Pulman, Manny Rayner, Arnold G. Smith (SRI, CUCL)

An explanation of the name

Core Language Engine

This is a gem, because

CLE distinguishes several distinct stages in the processing of the semantic representation. CLE uses unification for semantic composition.

Characteristics

Programming language
Prolog
Natural language
English
Type of analysis
Semantics-based
Language constructs
Noun Phrases, Verb Phrases, Preposition Phrases, Determiner Phrases, ADVerb Phrases, Relative Clauses, Conjunctions, Anaphora, Auxiliaries, Comparative expressions, Passives, Clefts, There be

Data flow

Natural Language input
Tokenize
  • Lexicon lookup
  • Morphological analysis
Tokens
Parse
Parser type
A "left corner" parser with top-down filtering
Grammar type
Generalized Phrase Structure Grammar
    Syntactic form
    Interpret
    • Semantic attachment
    • Semantic composition
      (unification)
    • Semantic conflict detection
    • Quantifier scoping
    • Anaphora resolution
    Semantic form
    (FOPC with extensions)
    • Event based
    • Uses constants for proper nouns
    • Custom ontology
    Convert
    • Syntactic rewrites
    Knowledge source form
    (Logical Form)
      Execute
      Knowledge Base
      A Prolog database
        Knowledge base answers
        Answer
          Natural Language output

          Books

          Articles