WordNet explained

WordNet
WordNet
Screenshot Size:300px
Developer:Princeton University
Released:mid 1980s
Latest Release Version:3.1
Latest Release Date:[1]
Programming Language:Prolog
Operating System:Unix, Linux, Solaris, Windows
Size:16MB (including 155,327 words organized in 175,979 synsets for a total of 207,016 word-sense pairs)
Language:More than 200 languages
Genre:Lexical database
Licence:BSD-like

WordNet is a lexical database of semantic relations between words that links words into semantic relations including synonyms, hyponyms, and meronyms. The synonyms are grouped into synsets with short definitions and usage examples. It can thus be seen as a combination and extension of a dictionary and thesaurus. While it is accessible to human users via a web browser,[2] its primary use is in automatic text analysis and artificial intelligence applications. It was first created in the English language[3] and the English WordNet database and software tools have been released under a BSD style license and are freely available for download from that WordNet website. There are now WordNets in more than 200 languages.[4]

History and team members

WordNet was first created in 1985, in English only, in the Cognitive Science Laboratory of Princeton University under the direction of psychology professor George Armitage Miller. It was later directed by Christiane Fellbaum. The project was initially funded by the U.S. Office of Naval Research, and later also by other U.S. government agencies including the DARPA, the National Science Foundation, the Disruptive Technology Office (formerly the Advanced Research and Development Activity) and REFLEX. George Miller and Christiane Fellbaum received the 2006 Antonio Zampolli Prize for their work with WordNet.

The Global WordNet Association is a non-commercial organization that provides a platform for discussing, sharing and connecting WordNets for all languages in the world. Christiane Fellbaum and Piek Th.J.M. Vossen are its co-presidents.[5]

Database contents

The database contains 155,327 words organized in 175,979 synsets for a total of 207,016 word-sense pairs; in compressed form, it is about 12 megabytes in size.[6]

It includes the lexical categories nouns, verbs, adjectives and adverbs but ignores prepositions, determiners and other function words.

Words from the same lexical category that are roughly synonymous are grouped into synsets, which include simplex words as well as collocations like "eat out" and "car pool." The different senses of a polysemous word form are assigned to different synsets. A synset's meaning is further clarified with a short defining gloss and one or more usage examples. An example adjective synset is:

good, right, ripe – (most suitable or right for a particular purpose; "a good time to plant tomatoes"; "the right time to act"; "the time is ripe for great sociological changes")

All synsets are connected by means of semantic relations. These relations, which are not all shared by all lexical categories, include:

Y is a hypernym of X if every X is a (kind of) Y (canine is a hypernym of dog)

Y is a hyponym of X if every Y is a (kind of) X (dog is a hyponym of canine)

Y is a holonym of X if X is a part of Y (building is a holonym of window)

Y is a meronym of X if Y is a part of X (window is a meronym of building)

the verb Y is a troponym of the verb X if the activity Y is doing X in some manner (to lisp is a troponym of to talk)

the verb Y is entailed by the verb X if by doing X you must be doing Y (to sleep is entailed by to snore)

These semantic relations hold among all members of the linked synsets. Individual synset members (words) can also be connected with lexical relations. For example, (one sense of) the noun "director" is linked to (one sense of) the verb "direct" from which it is derived via a "morphosemantic" link.

The morphology functions of the software distributed with the database try to deduce the lemma or stem form of a word from the user's input. Irregular forms are stored in a list, and looking up "ate" will return "eat," for example.

Knowledge structure

Both nouns and verbs are organized into hierarchies, defined by hypernym or IS A relationships. For instance, one sense of the word dog is found following hypernym hierarchy; the words at the same level represent synset members. Each set of synonyms has a unique index.

At the top level, these hierarchies are organized into 25 beginner "trees" for nouns and 15 for verbs (called lexicographic files at a maintenance level). All are linked to a unique beginner synset, "entity".Noun hierarchies are far deeper than verb hierarchies.

Adjectives are not organized into hierarchical trees. Instead, two "central" antonyms such as "hot" and "cold" form binary poles, while 'satellite' synonyms such as "steaming" and "chilly" connect to their respective poles via a "similarity" relations. The adjectives can be visualized in this way as "dumbbells" rather than as "trees".

Psycholinguistic aspects

The initial goal of the WordNet project was to build a lexical database that would be consistent with theories of human semantic memory developed in the late 1960s. Psychological experiments indicated that speakers organized their knowledge of concepts in an economic, hierarchical fashion. Retrieval time required to access conceptual knowledge seemed to be directly related to the number of hierarchies the speaker needed to "traverse" to access the knowledge. Thus, speakers could more quickly verify that canaries can sing because a canary is a songbird, but required slightly more time to verify that canaries can fly (where they had to access the concept "bird" on the superordinate level) and even more time to verify canaries have skin (requiring look-up across multiple levels of hyponymy, up to "animal").[7] While such psycholinguistic experiments and the underlying theories have been subject to criticism, some of WordNet's organization is consistent with experimental evidence. For example, anomic aphasia selectively affects speakers' ability to produce words from a specific semantic category, a WordNet hierarchy. Antonymous adjectives (WordNet's central adjectives in the dumbbell structure) are found to co-occur far more frequently than chance, a fact that has been found to hold for many languages.

As a lexical ontology

WordNet is sometimes called an ontology, a persistent claim that its creators do not make. The hypernym/hyponym relationships among the noun synsets can be interpreted as specialization relations among conceptual categories. In other words, WordNet can be interpreted and used as a lexical ontology in the computer science sense. However, such an ontology should be corrected before being used, because it contains hundreds of basic semantic inconsistencies; for example there are, (i) common specializations for exclusive categories and (ii) redundancies in the specialization hierarchy. Furthermore, transforming WordNet into a lexical ontology usable for knowledge representation should normally also involve (i) distinguishing the specialization relations into subtypeOf and instanceOf relations, and (ii) associating intuitive unique identifiers to each category. Although such corrections and transformations have been performed and documented as part of the integration of WordNet 1.7 into the cooperatively updatable knowledge base of WebKB-2,[8] most projects claiming to reuse WordNet for knowledge-based applications (typically, knowledge-oriented information retrieval) simply reuse it directly.

WordNet has also been converted to a formal specification, by means of a hybrid bottom-up top-down methodology to automatically extract association relations from it and interpret these associations in terms of a set of conceptual relations, formally defined in the DOLCE foundational ontology.[9]

In most works that claim to have integrated WordNet into ontologies, the content of WordNet has not simply been corrected when it seemed necessary; instead, it has been heavily reinterpreted and updated whenever suitable. This was the case when, for example, the top-level ontology of WordNet was restructured[10] according to the OntoClean-based approach, or when it was used as a primary source for constructing the lower classes of the SENSUS ontology.

Limitations

The most widely discussed limitation of WordNet (and related resources like ImageNet) is that some of the semantic relations are more suited to concrete concepts than to abstract concepts.[11] For example, it is easy to create hyponyms/hypernym relationships to capture that a "conifer" is a type of "tree", a "tree" is a type of "plant", and a "plant" is a type of "organism", but it is difficult to classify emotions like "fear" or "happiness" into equally deep and well-defined hyponyms/hypernym relationships.

Many of the concepts in WordNet are specific to certain languages and the most accurate reported mapping between languages is 94%.[12] Synonyms, hyponyms, meronyms, and antonyms occur in all languages with a WordNet so far, but other semantic relationships are language-specific.[13] This limits the interoperability across languages. However, it also makes WordNet a resource for highlighting and studying the differences between languages, so it is not necessarily a limitation for all use cases.

WordNet does not include information about the etymology or the pronunciation of words and it contains only limited information about usage. WordNet aims to cover most everyday words and does not include much domain-specific terminology.

WordNet is the most commonly used computational lexicon of English for word-sense disambiguation (WSD), a task aimed at assigning the context-appropriate meanings (i.e. synset members) to words in a text.[14] However, it has been argued that WordNet encodes sense distinctions that are too fine-grained. This issue prevents WSD systems from achieving a level of performance comparable to that of humans, who do not always agree when confronted with the task of selecting a sense from a dictionary that matches a word in a context. The granularity issue has been tackled by proposing clustering methods that automatically group together similar senses of the same word.[15] [16] [17]

Offensive content

WordNet includes words that can be perceived as pejorative or offensive.[18] The interpretation of a word can change over time and between social groups, so it is not always possible for WordNet to define a word as "pejorative" or "offensive" in isolation. Therefore, people using WordNet must apply their own methods to identify offensive or pejorative words.

However, this limitation is true of other lexical resources like dictionaries and thesauruses, which also contain pejorative and offensive words. Some dictionaries indicate words that are pejoratives, but do not include all the contexts in which words might be acceptable or offensive to different social groups. Therefore, people using dictionaries must apply their own methods to identify all offensive words.

Licensed vs. Open WordNets

Some wordnets were subsequently created for other languages. A 2012 survey lists the wordnets and their availability.[19] In an effort to propagate the usage of WordNets, the Global WordNet community had been slowly re-licensing their WordNets to an open domain where researchers and developers can easily access and use WordNets as language resources to provide ontological and lexical knowledge in natural-language processing (NLP) tasks.

The Open Multilingual WordNet[20] provides access to open licensed wordnets in a variety of languages, all linked to the Princeton Wordnet of English (PWN). The goal is to make it easy to use wordnets in multiple languages.

Applications

WordNet has been used for a number of purposes in information systems, including word-sense disambiguation, information retrieval, automatic text classification, automatic text summarization, machine translation and even automatic crossword puzzle generation.

A common use of WordNet is to determine the similarity between words. Various algorithms have been proposed, including measuring the distance among words and synsets in WordNet's graph structure, such as by counting the number of edges among synsets. The intuition is that the closer two words or synsets are, the closer their meaning. A number of WordNet-based word similarity algorithms are implemented in a Perl package called WordNet::Similarity,[21] and in a Python package called NLTK.[22] Other more sophisticated WordNet-based similarity techniques include ADW,[23] whose implementation is available in Java. WordNet can also be used to inter-link other vocabularies.[24]

Interfaces

Princeton maintains a list of related projects[25] that includes links to some of the widely used application programming interfaces available for accessing WordNet using various programming languages and environments.

Related projects and extensions

WordNet is connected to several databases of the Semantic Web. WordNet is also commonly reused via mappings between the WordNet synsets and the categories from ontologies. Most often, only the top-level categories of WordNet are mapped.

Global WordNet Association

The Global WordNet Association (GWA)[26] is a public and non-commercial organization that provides a platform for discussing, sharing and connecting wordnets for all languages in the world. The GWA also promotes the standardization of wordnets across languages, to ensure its uniformity in enumerating the synsets in human languages. The GWA keeps a list of wordnets developed around the world.[27]

Other languages

Projects such as BalkaNet and EuroWordNet made it feasible to create standalone wordnets linked to the original one. Two such projects were the Russian WordNet, patronized by Petersburg State University of Means of Communication[46] and led by S.A. Yablonsky,[47] and Russnet,[48] by Saint Petersburg State University.

Linked data

Related projects

Distributions

WordNet Database is distributed as a dictionary package (usually a single file) for the following software:

See also

External links

Notes and References

  1. Web site: WordNet News.
  2. Web site: WordNet Search - 3.1.
  3. 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.
  4. Web site: WordNets in the World . Global WordNet Association . 19 January 2020.
  5. Web site: About Global WordNet Association . Global WordNet . 19 January 2020.
  6. Web site: WordNet Statistics . Wordnet.princeton.edu . 2018-06-22.
  7. Collins A., Quillian M. R. 1972. Experiments on Semantic Memory and Language Comprehension. In Cognition in Learning and Memory. Wiley, New York.
  8. Web site: Integration of WordNet 1.7 in WebKB-2. Webkb.org . 2014-03-11.
  9. Book: A. . Gangemi . R. . Navigli . P. . Velardi . The OntoWordNet Project: Extension and Axiomatization of Conceptual Relations in WordNet . Proc. of International Conference on Ontologies, Databases and Applications of SEmantics (ODBASE 2003) . Catania, Sicily (Italy) . 2003 . 820–838.
  10. A. . Oltramari . A. . Gangemi . N. . Guarino . C. . Masolo . 2002 . Restructuring WordNet's Top-Level: The OntoClean approach . 10.1.1.19.6574 . OntoLex'2 Workshop, Ontologies and Lexical Knowledge Bases (LREC 2002) . Las Palmas, Spain . 17–26 .
  11. Rudnicka . Ewa . Bond . Francis . Grabowski . Łukasz . Piasecki . Maciej . Piotrowski . Tadeusz . Lexical Perspective on Wordnet to Wordnet Mapping . Proceedings of the 9th Global WordNet Conference (GWC 2018) . 2018 . 210.
  12. Bond . Francis . Foster . Ryan . Linking and Extending an Open Multilingual Wordnet . Proceedings of the 51st Annual Meeting of the Association for Computational Linguistics . 2013 . 1352–1362 . 20 January 2020.
  13. Fellbaum . Christiane . Vossen . Piek . Challenges for a multilingual wordnet . Language Resources and Evaluation . 2012 . 46 . 2 . 313–326. 10.1007/s10579-012-9186-z . 10117946 .
  14. R. Navigli. Word Sense Disambiguation: A Survey, ACM Computing Surveys, 41(2), 2009, pp. 1–69
  15. E. Agirre, O. Lopez. 2003.Clustering WordNet Word Senses. In Proc. of the Conference on Recent Advances on Natural Language (RANLP’03), Borovetz, Bulgaria, pp. 121–130.
  16. R. Navigli. Meaningful Clustering of Senses Helps Boost Word Sense Disambiguation Performance, In Proc. of the 44th Annual Meeting of the Association for Computational Linguistics joint with the 21st International Conference on Computational Linguistics (COLING-ACL 2006), Sydney, Australia, July 17-21st, 2006, pp. 105–112.
  17. R. Snow, S. Prakash, D. Jurafsky, A. Y. Ng. 2007. Learning to Merge Word Senses, In Proc. of the 2007 Joint Conference on Empirical Methods in Natural Language Processing and Computational Natural Language Learning (EMNLP-CoNLL), Prague, Czech Republic, pp. 1005–1014.
  18. Web site: Wong . Julia Carrie . Julia Carrie Wong . 2019-09-18 . The viral selfie app ImageNet Roulette seemed fun – until it called me a racist slur . 2022-10-14 . the Guardian . en.
  19. Francis Bond and Kyonghee Paik 2012a. A survey of wordnets and their licenses. In Proceedings of the 6th Global WordNet Conference (GWC 2012). Matsue. 64–71
  20. Web site: Open Multilingual Wordnet. compling.hss.ntu.edu.sg. 10 April 2018.
  21. Web site: Ted Pedersen - WordNet::Similarity . D.umn.edu . 2008-06-16 . 2014-03-11.
  22. https://likegeeks.com/nlp-tutorial-using-python-nltk NLP using Python NLTK
  23. M. T. Pilehvar, D. Jurgens and R. Navigli. Align, Disambiguate and Walk: A Unified Approach for Measuring Semantic Similarity.. Proc. of the 51st Annual Meeting of the Association for Computational Linguistics (ACL 2013), Sofia, Bulgaria, August 4–9, 2013, pp. 1341-1351.
  24. Ballatore A, etal . 20. 2. 1404.5372. Annals of GIS . Linking geographic vocabularies through WordNet . 2014. 73–84. 10.1080/19475683.2014.904440. 2014AnGIS..20...73B. 9246582.
  25. Web site: Related projects - WordNet - Related projects . Wordnet.princeton.edu . 2014-01-06 . 2018-06-22.
  26. Web site: The Global WordNet Association . globalwordnet.org . globalwordnet.org . 2010-02-04 . 2014-03-11.
  27. Web site: Wordnets in the World. https://web.archive.org/web/20111021114613/http://www.globalwordnet.org/gwa/wordnet_table.html . 2011-10-21.
  28. Black W., Elkateb S., Rodriguez H., Alkhalifa M., Vossen P., Pease A., Bertran M., Fellbaum C., (2006) The Arabic WordNet Project, Proceedings of LREC 2006
  29. Lahsen Abouenour, Karim Bouzoubaa, Paolo Rosso (2013) On the evaluation and improvement of Arabic WordNet coverage and usability, Language Resources and Evaluation 47(3) pp 891–917
  30. D. Tufis, D. Cristea, S. Stamou. 2004. Balkanet: Aims, methods, results and perspectives. A general overview. Romanian J. Sci. Tech. Inform. (Special Issue on Balkanet), 7(1-2), pp. 9–43.
  31. Web site: BulNet . dcl.bas.bg . 2015-05-07.
  32. http://lope.linguistics.ntu.edu.tw/cwn/ Chinese Wordnet (中文詞彙網路) official page
  33. P. Vossen, Ed. 1998. EuroWordNet: A Multilingual Database with Lexical Semantic Networks. Kluwer, Dordrecht, The Netherlands.
  34. Web site: The Global WordNet Association . Globalwordnet.org . 2010-02-04 . 2014-01-05.
  35. Web site: FinnWordNet – The Finnish WordNet - Department of General Linguistics . Ling.helsinki.fi . 2014-01-05.
  36. Web site: GermaNet . Sfs.uni-tuebingen.de . 2014-03-11.
  37. Pushpak Bhattacharyya, IndoWordNet, Lexical Resources Engineering Conference 2010 (LREC 2010), Malta, May, 2010.
  38. C. Mouton, G. de Chalendar. 2010.JAWS : Just Another WordNet Subset. In Proc. of TALN 2010.
  39. http://malayalamwordnet.cusat.ac.in/ Website
  40. Web site: MCR 3.0 | Adimen . Adimen.si.ehu.es . 2022-03-21.
  41. E. Pianta, L. Bentivogli, C. Girardi. 2002. MultiWordNet: Developing an aligned multilingual database. In Proc. of the 1st International Conference on Global WordNet, Mysore, India, pp. 21–25.
  42. Web site: Open Dutch WordNet . Wordpress.let.vupr.nl . 2015-10-28 . 2022-03-21.
  43. Web site: arademaker/openWordnet-PT — GitHub . Github.com . 2014-01-05.
  44. http://plwordnet.pwr.wroc.pl/wordnet/ official webpage
  45. http://www.ltc.amu.edu.pl/polnet/ official webpage
  46. Web site: Русский WordNet . Pgups.ru . 2014-01-05.
  47. Balkova. Valentina. Sukhonogov. Andrey. Yablonsky. Sergey. Russian WordNet From UML-notation to Inter net/Intranet Database Implementation. GWC 2004 Proceedings. 2003. 31–38. 12 March 2017.
  48. Web site: RussNet: Главная страница . Project.phil.spbu.ru . 2014-03-11.
  49. Web site: UWN: Towards a Universal Multilingual Wordnet - D5: Databases and Information Systems (Max-Planck-Institut für Informatik) . Mpi-inf.mpg.de . 2011-08-14 . 2014-01-05.
  50. S. Benoît, F. Darja. 2008. Building a free French wordnet from multilingual resources. In Proc. of Ontolex 2008, Marrakech, Maroc.
  51. R. Navigli, S. P. Ponzetto. BabelNet: Building a Very Large Multilingual Semantic Network. Proc. of the 48th Annual Meeting of the Association for Computational Linguistics (ACL 2010), Uppsala, Sweden, July 11–16, 2010, pp. 216–225.
  52. I. Niles, A. Pease 2001. Toward a Standard Upper Ontology: A large ontology for the Semantic Web and its applications. In Proceedings of the 2nd International Conference on Formal Ontology in Information Systems (FOIS-2001),
  53. I. Niles, A. Pease 2003. Linking Lexicons and Ontologies: Mapping WordNet to the Suggested Upper Merged Ontology, In Proceedings of the IEEE International Conference on Information and Knowledge Engineering, pp 412-416
  54. S. Reed and D. Lenat. 2002. Mapping Ontologies into Cyc. In Proc. of AAAI 2002 Conference Workshop on Ontologies For The Semantic Web, Edmonton, Canada, 2002
  55. Masolo, C., Borgo, S., Gangemi, A., Guarino, N., Oltramari, A., Schneider, L.S. 2002. WonderWeb Deliverable D17. The WonderWeb Library of Foundational Ontologies and the DOLCE ontology. Report (ver. 2.0, 15-08-2002)
  56. Gangemi, A., Guarino, N., Masolo, C., Oltramari, A. 2003 Sweetening WordNet with DOLCE. In AI Magazine 24(3): Fall 2003, pp. 13–24
  57. C. Bizer, J. Lehmann, G. Kobilarov, S. Auer, C. Becker, R. Cyganiak, S. Hellmann, DBpedia – A crystallization point for the Web of Data. Web Semantics, 7(3), 2009, pp. 154–165
  58. S. M. Harabagiu, G. A. Miller, D. I. Moldovan. 1999. WordNet 2 – A Morphologically and Semantically Enhanced Resource. In Proc. of the ACL SIGLEX Workshop: Standardizing Lexical Resources, pp. 1–8.
  59. J. Deng, W. Dong, R. Socher, L. Li, K. Li, L. Fei-Fei. ImageNet: A Large-Scale Hierarchical Image Database. In Proc. of 2009 IEEE Conference on Computer Vision and Pattern Recognition
  60. M. Poprat, E. Beisswanger, U. Hahn. 2008. Building a BIOWORDNET by Using WORDNET’s Data Formats and WORDNET’s Software Infrastructure – A Failure Story. In Proc. of the Software Engineering, Testing, and Quality Assurance for Natural Language Processing Workshop, pp. 31–39.
  61. S. Ponzetto, R. Navigli. Large-Scale Taxonomy Mapping for Restructuring and Integrating Wikipedia, In Proc. of the 21st International Joint Conference on Artificial Intelligence (IJCAI 2009), Pasadena, California, July 14-17th, 2009, pp. 2083–2088.
  62. S. P. Ponzetto, R. Navigli. Knowledge-rich Word Sense Disambiguation rivaling supervised systems. In Proc. of the 48th Annual Meeting of the Association for Computational Linguistics (ACL), 2010, pp. 1522–1531.
  63. S. Baccianella, A. Esuli and F. Sebastiani. SentiWordNet 3.0: An Enhanced Lexical Resource for Sentiment Analysis and Opinion Mining. In Proceedings of the 7th Conference on Language Resources and Evaluation (LREC'10), Valletta, MT, 2010, pp. 2200–2204.
  64. Piek Vossen, Claudia Soria, Monica Monachini: Wordnet-LMF: a standard representation for multilingual wordnets, in LMF Lexical Markup Framework, edited by Gil Francopoulo ISTE / Wiley 2013
  65. Web site: Babylon WordNet . Babylon.com . 2014-03-11.
  66. Web site: GoldenDict - Browse /dictionaries at Sourceforge.net . Sourceforge.net . 2010-12-01 . 2014-01-05.
  67. Web site: Lingoes WordNet . Lingoes.net . 2007-11-16 . 2014-03-11.

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