Natural-language understanding

Source: Wikipedia, the free encyclopedia.

Natural-language understanding (NLU) or natural-language interpretation (NLI)

AI-hard problem.[2]

There is considerable commercial interest in the field because of its application to

.

History

The program

MIT, is one of the earliest known attempts at natural-language understanding by a computer.[6][7][8][9][10] Eight years after John McCarthy coined the term artificial intelligence
, Bobrow's dissertation (titled Natural Language Input for a Computer Problem Solving System) showed how a computer could understand simple natural language input to solve algebra word problems.

A year later, in 1965, Joseph Weizenbaum at MIT wrote ELIZA, an interactive program that carried on a dialogue in English on any topic, the most popular being psychotherapy. ELIZA worked by simple parsing and substitution of key words into canned phrases and Weizenbaum sidestepped the problem of giving the program a database of real-world knowledge or a rich lexicon. Yet ELIZA gained surprising popularity as a toy project and can be seen as a very early precursor to current commercial systems such as those used by Ask.com.[11]

In 1969,

Janet Kolodner
.

In 1970,

finite state automata
that were called recursively. ATNs and their more general format called "generalized ATNs" continued to be used for a number of years.

In 1971, Terry Winograd finished writing SHRDLU for his PhD thesis at MIT. SHRDLU could understand simple English sentences in a restricted world of children's blocks to direct a robotic arm to move items. The successful demonstration of SHRDLU provided significant momentum for continued research in the field.[14][15] Winograd continued to be a major influence in the field with the publication of his book Language as a Cognitive Process.[16] At Stanford, Winograd would later advise Larry Page, who co-founded Google.

In the 1970s and 1980s, the natural language processing group at

Symantec Corporation originally as a company for developing a natural language interface for database queries on personal computers. However, with the advent of mouse-driven graphical user interfaces, Symantec changed direction. A number of other commercial efforts were started around the same time, e.g., Larry R. Harris at the Artificial Intelligence Corporation and Roger Schank and his students at Cognitive Systems Corp.[17][18] In 1983, Michael Dyer developed the BORIS system at Yale which bore similarities to the work of Roger Schank and W. G. Lehnert.[19]

The third millennium saw the introduction of systems using machine learning for text classification, such as the IBM

Watson. However, experts debate how much "understanding" such systems demonstrate: e.g., according to John Searle, Watson did not even understand the questions.[20]

Patom Theory, supports this assessment. Natural language processing has made inroads for applications to support human productivity in service and e-commerce, but this has largely been made possible by narrowing the scope of the application. There are thousands of ways to request something in a human language that still defies conventional natural language processing.[citation needed] According to Wibe Wagemans, "To have a meaningful conversation with machines is only possible when we match every word to the correct meaning based on the meanings of the other words in the sentence – just like a 3-year-old does without guesswork."[21]

Scope and context

The umbrella term "natural-language understanding" can be applied to a diverse set of computer applications, ranging from small, relatively simple tasks such as short commands issued to robots, to highly complex endeavors such as the full comprehension of newspaper articles or poetry passages. Many real-world applications fall between the two extremes, for instance text classification for the automatic analysis of emails and their routing to a suitable department in a corporation does not require an in-depth understanding of the text,[22] but needs to deal with a much larger vocabulary and more diverse syntax than the management of simple queries to database tables with fixed schemata.

Throughout the years various attempts at processing natural language or English-like sentences presented to computers have taken place at varying degrees of complexity. Some attempts have not resulted in systems with deep understanding, but have helped overall system usability. For example,

first order logic
) of the semantics of natural language sentences.

Hence the breadth and depth of "understanding" aimed at by a system determine both the complexity of the system (and the implied challenges) and the types of applications it can deal with. The "breadth" of a system is measured by the sizes of its vocabulary and grammar. The "depth" is measured by the degree to which its understanding approximates that of a fluent native speaker. At the narrowest and shallowest, English-like command interpreters require minimal complexity, but have a small range of applications. Narrow but deep systems explore and model mechanisms of understanding,[25] but they still have limited application. Systems that attempt to understand the contents of a document such as a news release beyond simple keyword matching and to judge its suitability for a user are broader and require significant complexity,[26] but they are still somewhat shallow. Systems that are both very broad and very deep are beyond the current state of the art.

Components and architecture

Regardless of the approach used, most natural-language-understanding systems share some common components. The system needs a

Wordnet lexicon required many person-years of effort.[27]

The system also needs theory from

Semantic parsers convert natural-language texts into formal meaning representations.[32]

Advanced applications of natural-language understanding also attempt to incorporate logical

logical deduction to arrive at conclusions. Therefore, systems based on functional languages such as Lisp need to include a subsystem to represent logical assertions, while logic-oriented systems such as those using the language Prolog generally rely on an extension of the built-in logical representation framework.[33][34]

The management of

context in natural-language understanding can present special challenges. A large variety of examples and counter examples have resulted in multiple approaches to the formal modeling of context, each with specific strengths and weaknesses.[35][36]

See also

Notes

  1. ^ Semaan, P. (2012). Natural Language Generation: An Overview. Journal of Computer Science & Research (JCSCR)-ISSN, 50-57
  2. ^ Roman V. Yampolskiy. Turing Test as a Defining Feature of AI-Completeness . In Artificial Intelligence, Evolutionary Computation and Metaheuristics (AIECM) --In the footsteps of Alan Turing. Xin-She Yang (Ed.). pp. 3-17. (Chapter 1). Springer, London. 2013. http://cecs.louisville.edu/ry/TuringTestasaDefiningFeature04270003.pdf
  3. ^ Van Harmelen, Frank, Vladimir Lifschitz, and Bruce Porter, eds. Handbook of knowledge representation. Vol. 1. Elsevier, 2008.
  4. ^ Macherey, Klaus, Franz Josef Och, and Hermann Ney. "Natural language understanding using statistical machine translation." Seventh European Conference on Speech Communication and Technology. 2001.
  5. ^ Hirschman, Lynette, and Robert Gaizauskas. "Natural language question answering: the view from here." natural language engineering 7.4 (2001): 275-300.
  6. American Association for Artificial Intelligence Brief History of AI [1]
  7. .
  8. page 286
  9. , p. 19
  10. page 278
  11. pages 188-189
  12. ^ Roger Schank, 1969, A conceptual dependency parser for natural language Proceedings of the 1969 conference on Computational linguistics, Sång-Säby, Sweden, pages 1-3
  13. ^ Woods, William A (1970). "Transition Network Grammars for Natural Language Analysis". Communications of the ACM 13 (10): 591–606 [2]
  14. page 89
  15. ^ Terry Winograd's SHRDLU page at Stanford SHRDLU
  16. ^ Winograd, Terry (1983), Language as a Cognitive Process, Addison–Wesley, Reading, MA.
  17. ^ Larry R. Harris, Research at the Artificial Intelligence corp. ACM SIGART Bulletin, issue 79, January 1982 [3]
  18. page xiii
  19. ^ Searle, John (23 February 2011). "Watson Doesn't Know It Won on 'Jeopardy!'". Wall Street Journal.
  20. ^ Brandon, John (2016-07-12). "What Natural Language Understanding tech means for chatbots". VentureBeat. Retrieved 2024-02-29.
  21. ^ InfoWorld, Nov 13, 1989, page 144
  22. ^ InfoWorld, April 19, 1984, page 71
  23. ^ Building Working Models of Full Natural-Language Understanding in Limited Pragmatic Domains by James Mason 2010 [4]
  24. page 289
  25. ^ G. A. Miller, R. Beckwith, C. D. Fellbaum, D. Gross, K. Miller. 1990. WordNet: An online lexical database. Int. J. Lexicograph. 3, 4, pp. 235-244.
  26. page 209
  27. ^ Wong, Yuk Wah, and Raymond J. Mooney. "Learning for semantic parsing with statistical machine translation." Proceedings of the main conference on Human Language Technology Conference of the North American Chapter of the Association of Computational Linguistics. Association for Computational Linguistics, 2006.
  28. page 111
  29. ^ Programming with Natural Language Is Actually Going to Work—Wolfram Blog
  30. ^ Van Valin, Jr, Robert D. "From NLP to NLU" (PDF).
  31. ^ Ball, John. "multi-lingual NLU by Pat Inc". Pat.ai.