Computing and Linguistics: A cognitive approach

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Introduction to Topic Maps for (cognitive) linguists and a first attempt to relate the model of Topic Maps to Langacker's Cognitive Grammar.

Introduction to Topic Maps for (cognitive) linguists and a first attempt to relate the model of Topic Maps to Langacker's Cognitive Grammar.

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  • 1. www.ontopedia.net O N T O P E D I A The Identity of Everything Computing and Linguistics A Cognitive Approach or, Computing “As We May Think” Steve Pepper pepper.steve@gmail.com University of Oslo, 2009-04-21
  • 2. www.ontopedia.net O N T O P E D I A The Identity of Everything Today’s “research questions”  How can linguistics – and in particular cognitive linguistics – inform our work with Topic Maps?  Can Topic Maps contribute in any way to the cognitive linguistics project?  Plan of action – I tell you about Topic Maps (conceptual model) – I draw some parallels with natural language – You correct me, elaborate and suggest new directions
  • 3. www.ontopedia.net O N T O P E D I A The Identity of Everything Relevance to you as linguists  As users of the technology – organizing data collected in your research  As consultants to users of the technology – e.g. universities, government agencies, private enterprise  As contributors to the standard – clarify some of the cognitive issues, establish best practices, help extend the standard  As lobbyists to the University of Oslo – if you think the new UiO web site should be based on Topic Maps, please make your views known to the project group: http://www.admin.uio.no/prosjekter/nyuioweb/
  • 4. www.ontopedia.net O N T O P E D I A The Identity of Everything Relevance in general 1. We need to organize information in a new way – The summation of human experience is being expanded at a prodigious rate, and the means we use for threading through the consequent maze to the momentarily important item is the same as was used in the days of square-rigged ships. (Vannevar Bush, As We May Think, 1945) 2. We need new ways of managing knowledge – In today’s global knowledge economy, knowledge is the key asset in many organizations...  Topic Maps makes major contributions in both areas – See the use cases presented at recent Topic Maps conferences http://www.topicmaps.com
  • 5. www.ontopedia.net O N T O P E D I A The Identity of Everything What is Topic Maps?  An ISO standard for computer-based information and knowledge management – “Provides the ability to control infoglut and share knowledge by connecting any kind of information from any kind of source based on its meaning”  A “semantic technology” – Cf. Semantic Web (RDF, OWL) – A form of knowledge representation (primitive perhaps, but useful)  Widely used for web-based delivery of information – Plus: Information Integration, eLearning, Business Process Modeling, Product Configuration, Business Rules Management, Asset Management, Knowledge Management, …
  • 6. www.ontopedia.net O N T O P E D I A The Identity of Everything The problem with computing...  ...is that it’s inside-out!  People used to think the sun revolved around the earth – Copernicus’ heliocentric theory turned this idea inside out and revolutionized our understanding of the universe  Today we face a similar situation in computing – Our computing universe has computers, applications and documents at the centre – The concepts that our information is about are somewhere in outer space where they can’t be found
  • 7. www.ontopedia.net O N T O P E D I A The Identity of Everything A subject-centric revolution  This is wrong, because it does not reflect how humans think – We think in terms of interrelated concepts (or subjects) – Subjects are what interest us, not documents or applications – And so subjects must be given centre stage  We need a subject-centric revolution – This has ramifications for every aspect of human-computer interaction, including user interfaces, operating systems, file systems, etc. – Consider the typical user desktop...
  • 8. www.ontopedia.net O N T O P E D I A The Identity of Everything Today ourToday our desktops aredesktops are application-application- centric andcentric and document-document- centriccentric Icons representIcons represent applicationsapplications andand documentsdocuments
  • 9. www.ontopedia.net O N T O P E D I A The Identity of Everything topic maps tm2008 bantu semantics LING 2110 INF 2820rana keynote OOXML K185 gambia opera janacek bayreuth håkon TM2008 Topic page Emails Documents Web pages Copy PSIΨ  Why can’t they be subject-centric, with icons that represent the subjects we are interested in?  With links between related icons?  And with context menus that allow us to find everything related to a particular subject? TM2008 Topic page Emails Documents Web pages Copy PSIΨ
  • 10. www.ontopedia.net O N T O P E D I A The Identity of Everything Computing “As We May Think”  Bush’s solution to information overload: – Organize information “As We May Think”, i.e. associatively  His vision spawned the hypertext movement – Doug Engelbart, Ted Nelson, Bill Atkinson, Tim Berners-Lee, ... – The World Wide Web is its greatest triumph to date  But hypertext does not correspond to how we think – Our heads are not full of millions of interlinked documents – They are full of “interlinked” concepts (or subjects)  Topic Maps provides a close approximation to this – It is a technology that is based on cognitive principles
  • 11. www.ontopedia.net O N T O P E D I A The Identity of Everything Background to Topic Maps  Emerged from the SGML community in 1990’s – Use case: How to merge (digital) back-of-book indexes – Some input from library science – No input from linguists – Precious little input from computer scientists before 2001 – Most of the SGML community came from the humanities  ISO 13250 first published in 2000 (recently revised) – A model for representing knowledge organization structures (indexes, glossaries, thesauri, encyclopedias) – Plus interchange syntax, query language, constraint language, ...  Widely adopted in Norway (esp. public sector) – And gaining ground elsewhere
  • 12. www.ontopedia.net O N T O P E D I A The Identity of Everything The TAO of Topic Maps  The core concepts are derived from the back-of-book index  Extended and generalized for use with digital information  Consider a two-layer model consisting of – a set of information resources (below) – a “knowledge map” (above)  This is like the division of a book into content and index knowledge layer information layer (INDEX) (CONTENT) Callas, Maria …………………… 42 Cavalleria Rusticana … 71, 203-204 Mascagni, Pietro Cavalleria Rusticana . 71, 203-204 Pavarotti, Luciano ……………… 45 Puccini, Giacomo ………. 23, 26-31 Tosca ………………. 65, 201-202 Rustic Chivalry, see Cavalleria Rusticana singers ………………………. 39-52 baritone ………………………. 46 bass ……………………….. 46-47 soprano ……………… 41-42, 337 tenor ………………………. 44-45 see also Callas, Pavarotti Tosca ………………… 65, 201-202
  • 13. www.ontopedia.net O N T O P E D I A The Identity of Everything (1) The information layer  The lower layer contains the content – usually digital, but need not be – can be in any format or notation or location – can be text, graphics, video, audio – whatever  This is like the content of the book to which the back-of-book index belongs information layer(CONTENT)
  • 14. www.ontopedia.net O N T O P E D I A The Identity of Everything (2) The knowledge layer  The upper layer consists of (typed) topics and associations – Topics represent the subjects that the information is about  Like the list of topics that forms a back-of-book index – Associations represent relationships between those subjects  Like “see also” relationships in a back-of-book index knowledge layer composed by born in composed by Puccini Tosca Lucca Madame Butterfly (INDEX) Domain: Italian opera
  • 15. www.ontopedia.net O N T O P E D I A The Identity of Everything Occurrences link the layers  Occurrences represent relationships between information resources and the subjects that they are “about”  The links (or locators) are like page numbers in a back-of-book index  Occurrences can also be typed (e.g. bio, map, synopsis) knowledge layer information layer Puccini Tosca Lucca composed by born in composed by Madame Butterfly
  • 16. www.ontopedia.net O N T O P E D I A The Identity of Everything Summary of core concepts A pool of information or data, and information Associations – representing relationships between subjects composed by born in composed by Occurrences – links to information that is somehow relevant to a given subject = The TAO of Topic Maps a knowledge layer consisting of knowledge Topics – a set of topics representing the key subjects of the domain in question Puccini Tosca Lucca Madame Butterfly Let’s look at some TAOs in the Omnigator… Plus: topic types, association types, occurrence types – each of which are represented by topics...
  • 17. www.ontopedia.net O N T O P E D I A The Identity of Everything About the Omnigator  A free topic map browser from Ontopia – Download from http://www.ontopia.net (part of “OKS Samplers”) – Java-based, runs on any computer  Completely generic – Not optimized for any particular ontology – Display and navigate any conforming topic map  A teaching aid – Not designed for end-users (no attempt to hide technical jargon) – Also used for prototyping and debugging  Not to be used for most real world applications! – These require custom interfaces based on a specific ontology – (see http://www.topicmaps.com for a good example)
  • 18. www.ontopedia.net O N T O P E D I A The Identity of Everything Omnigator interface current topic multiple (typed) names topic type(s) typed occurrences (internal and external) typed associations Demo a typical topic page identifier(s)
  • 19. www.ontopedia.net O N T O P E D I A The Identity of Everything Typing topics revisited  Basic building blocks of the TAO model are – Topics: e.g. “Puccini”, “Lucca”, “Tosca” – Associations: e.g. “Puccini was born in Lucca” – Occurrences: e.g. “http://www.opera.net/puccini/bio.html is a biography of Puccini”  Each of these constructs can be typed – Topic types: “composer”, “city”, “opera” – Association types: “born in”, “composed by” – Occurrence types: “biography”, “street map”, “synopsis”  All such types are also topics – The set of typing topics constitutes an ontology
  • 20. www.ontopedia.net O N T O P E D I A The Identity of Everything Capabilities of the TAO model (1)  Represent subjects explicitly – Topics represent the “things” users are interested in  Capture relationships between subjects – Associations provide user-friendly navigation paths to information (navigation “as we may think”) – Associations also promote serendipitous knowledge discovery through browsing  Make information findable – Topics provide a “one-stop-shop” for everything that is known about a subject (collocation of information and knowledge) – Occurrences allow information about a common subject to be aggregated across multiple systems, irrespective of location
  • 21. www.ontopedia.net O N T O P E D I A The Identity of Everything Capabilities of the TAO model (2)  Represent taxonomies and thesauri – Associations can (also) represent hierarchical relationships – With Topic Maps you can have multiple, interlinked hierarchies and faceted classification  Transcend simple hierarchies – Rich associative structures capture the complexity of knowledge and reflect the way people think  Manage knowledge – The topic map is the embodiment of “organizational memory” – Provides a structured way to capture people’s knowledge of things, events, relationships, etc.
  • 22. www.ontopedia.net O N T O P E D I A The Identity of Everything Beyond the TAO  Formal data model – Topic maps can be queried, e.g. – Give me all composers that composed operas that were based on plays that were written by Shakespeare  Interchange syntax – Topic maps can be interchanged – Increased reuse = added value  Robust identity model – Topic maps can be merged – Potential to federate knowledge  Scope – Topic maps can capture context  Reification – Topic maps can express different levels of detail – Similar to scaling in cartography For more details, see Pepper 2009
  • 23. www.ontopedia.net O N T O P E D I A The Identity of Everything Break – any questions so far? After the break: Topic Maps and natural language – towards a linguistic perspective
  • 24. www.ontopedia.net O N T O P E D I A The Identity of Everything Parallels with natural language  Basic grammatical classes  Nouns and verbs  Nominals and nouns  Clauses and verbs  Valency  Semantic roles  Categories and schemas  Hyponymy  Synonymy and homonymy  Nominalization  Grounding / co-reference  Information structure ⇒ TAO model ⇒ Topics and associations ⇒ Topics and their types ⇒ Associations and their types ⇒ Arity ⇒ Association roles ⇒ Typing topics ⇒ Type hierarchies ⇒ Naming ⇒ Reification ⇒ Subject identity / collocation ⇒ Navigation
  • 25. www.ontopedia.net O N T O P E D I A The Identity of Everything Basic principles, basic classes  In elementary school, I was taught that a noun is the name of a person, place, or thing. In college, I was taught the basic linguistic doctrine that a noun can only be defined in terms of grammatical behavior, conceptual definitions of grammatical classes being impossible. Here, several decades later, I demonstrate the inexorable progress of grammatical theory by claiming that a noun is the name of a thing. (Langacker 2008)  The basic grammatical classes are nouns and verbs – They prototypically profile things and relationships  They correspond to topics and associations
  • 26. www.ontopedia.net O N T O P E D I A The Identity of Everything Grounding  “Grounding is characteristic of the structure referred to in CG as nominals and finite clauses. More specifically, a nominal or a finite clause profiles a grounded instance of a thing or process type.”  “A noun designates a type of thing, and a verb a type of process.”  “A nominal or a finite clause profiles a grounded instance of a thing or process type.”  Nominal grounding (determiners and quantifiers) – the, this, that, some, a, each, every, no, any  Clausal grounding (mood and tense) – -s, -ed, may, will, should Langacker 2008: 259ff (esp. 264)
  • 27. www.ontopedia.net O N T O P E D I A The Identity of Everything Nouns and nominals  Topic types represent classes of topics – Conceptual “groupings of things”, e.g. composer, opera, city, ... – They correspond to Langacker’s nouns (“types of thing”) However, topics can have multiple names – (This is how we handle synonymy and multilingualism) – In one sense it is topic names that correspond to nouns  Topic instances represent individual subjects – They correspond to Langacker’s nominals (“instances of types”) – Their names are typically proper nouns, e.g. Puccini, Tosca, Lucca
  • 28. www.ontopedia.net O N T O P E D I A The Identity of Everything Verbs and clauses  Association types represent classes of relationships – They correspond to Langacker’s verbs (“types of process”) – (Often named accordingly, e.g. born in, composed by, killed by, ...)  Individual associations represent specific relationships – They correspond to Langacker’s clauses (“instances of processes”) – e.g. Puccini was born in Lucca; Tosca was composed by Puccini Langacker distinguishes processes (temporal) and non-processual relationships (non-temporal). The latter are (prototypically) profiled by adjectives, adverbs, prepositions, and participles. This distinction is not made explicitly in Topic Maps.  Note: There are two predefined association types – type-instance (the relationship between a topic and its type) – supertype-subtype (a relationship between types, see Hyponymy)
  • 29. www.ontopedia.net O N T O P E D I A The Identity of Everything Valency  Associations can involve one, two or more topics – Binary associations, e.g. Puccini composed Tosca, are most common and correspond to transitive verbs – Ternary associations, e.g. Tosca killed Scarpia with a knife, can correspond to ditransitive verbs – Unary associations, e.g. Turandot was unfinished, correspond (sort of) to intransitive verbs (or binary properties)  The arity of an association – Corresponds to the valency of a verb
  • 30. www.ontopedia.net O N T O P E D I A The Identity of Everything Semantic roles  An association does not have “directionality”  Instead of direction, Topic Maps uses roles – Roles are classified by type – Role types specify the nature of each topic’s involvement in the relationship. They correspond to semantic roles. – (Role types are also topics)  Role types are different from topic types... Puccini Tosca composed composed by composer work RDFTopic Maps
  • 31. www.ontopedia.net O N T O P E D I A The Identity of Everything Roles and types T R A Puccini R T Tosca T T T composer workcomposed T composer T opera The role type can be – the same as the role playing topic’s topic type (composer = composer) – a supertype of the topic type (work > opera) – a subtype of the topic type (teacher < person) – a subtype of the topic type’s supertype (source < work)
  • 32. www.ontopedia.net O N T O P E D I A The Identity of Everything Association roles Semantic roles  Italian Opera Topic Map – composed: composer, work – born in: person, place – appears in: character, work – based on: source, result – revision of: source, result – part of: part, whole – exponent of: person, style – located in: container, containee – pupil of: teacher, pupil  Association roles tend to be much more specific – Variable practice – as yet no established conventions – Might (cognitive) linguists have something to offer here?  (Frawley 1992) – (logical actors) agent, author, instrument – (logical recipients) patient, experiencer, benefactive – (spatial roles) theme, source, goal – (non-participant roles) locative, reason, purpose
  • 33. www.ontopedia.net O N T O P E D I A The Identity of Everything Naming of associations  Intuitive naming requires flexibility – i.e. multiple AT names that change depending on the “direction” of the association  Puccini was born in Lucca  Lucca was the birthplace of Puccini  Alternative CG view – Naming should be based on whether the agent or the theme is in focus  The focus becomes the trajector – Point of focus = Current topic  Some strategies...  Voice-based – Active / passive forms of the verb  composedVa / composedVp by – Works well in SVO languages. Less satisfactory with SOV.  Role-based  teacherN of/pupilN of  Nominalization  composition – Tends to be used by Japanese, Koreans (and Germans??)  Combinations  bornV in / birthplaceN of  partN of/consistsV of
  • 34. www.ontopedia.net O N T O P E D I A The Identity of Everything Categories and prototypes  Topic types define categories of things – But are they Aristotelian or prototypical categories?  Aristotelian – Category membership is binary – All instances are equally representative. No standard notion of “similarity”.  Prototypical – Not defined by “necessary and sufficient conditions” (cf. OWL)  The decision is up to the conceptualizer (a.k.a. topic map author) – A topic can have more than one type  Boïto is a composer and a librettist – The same topic can be a topic type and a role type  e.g. Puccini is a composer; Puccini plays the role of composer in … – Should we establish conventions for goodness of example?  Could be useful in automated classification
  • 35. www.ontopedia.net O N T O P E D I A The Identity of Everything Schemas and constraints  Other types can also be said to define categories – association types, (occurrence types, name types, role types)  But these are more schematic (in the CG sense) – Schemas are “abstract templates obtained by reinforcing the commonality inherent in a set of instances” (Langacker 2008, p.23, in the context of grammatical rules)  Rules can be defined as templates and constraints: T R A Puccini R T Tosca T T T composer workcomposed T composer T opera “Puccini composed Tosca” The composer Puccini plays the role of composer in the “composition” relationship in which the role of work is played by the opera Tosca.T AGENT T THEMEelaboration sites
  • 36. www.ontopedia.net O N T O P E D I A The Identity of Everything Hyponymy  Topic Maps has two predefined association types: – type-instance (relationship between a topic and its type) – supertype-subtype (relationship between the denotations of a hyponym and its hyperonym) Mammal Primate Canine HumanChimp WolfDog Steve Ron LEGEND types instances supertype-subtype type-instance
  • 37. www.ontopedia.net O N T O P E D I A The Identity of Everything Synonymy and homonymy  Synonyms – One subject, multiple names – In thesauri: USE and USED FOR  TMs are subject-centric – A topic can have multiple names – Names can be typed  Typical name types: – nickname, synonym, alternate name – Context can be expressed using scope  Typically names in different natural languages – composer, komponist, 작곡가 , ... – Names can also have “variants”  Often used to capture orthographic variation: – Tchaikovsky, Чайко́вский, Tsjajkovskij, Tschaikowski  Also useful for sort names, pronunciation, etc.  Homonyms – One name, multiple subjects – In thesauri: problematic  TMs are based on identifiers – Same name can be used by more than one topic – Disambiguation in UI is left to the application – Two main disambiguation strategies  Default: qualify by type, e.g. – Tosca (opera) vs. Tosca (character)  Fallback: qualify by some other relationship, e.g. – Paris (France) vs. Paris (Texas) – La Bohème (Puccini) vs. La Bohème (Leoncavallo)
  • 38. www.ontopedia.net O N T O P E D I A The Identity of Everything Nominalization  (A topic map consists of assertions about subjects)  Assertions are made using statements: – names, e.g. a certain subject has the name “Tosca” – associations, e.g. “Tosca is set in Rome” – occurrences, e.g. “http://en.wikipedia.org/wiki/Rome is a web page about Rome”  Any statement can be reified – Reification results in a topic that has the same referent as the reified statement – e.g. Tosca is set in RomeA ⇒ The setting of Tosca in RomeT – The (new) reifying topic can have names and occurrences, and it can play roles in associations Derivation of nouns from other words, including verbs, adjectives etc. e.g. meetV ⇒ meetingN
  • 39. www.ontopedia.net O N T O P E D I A The Identity of Everything Subjects and topics  Topics represent subjects – the topic is the representation – the subject is the referent  Or, in Saussure’s terms – signifiant and signifié  A subject can be anything: A subject is any “thing” whatsoever, whether or not it exists or has any other specific characteristics, about which anything whatsoever may be asserted by any means whatsoever.  Is the topic/subject pairing a symbolic assembly? A subject in the real world T A topic in the computer domain
  • 40. www.ontopedia.net O N T O P E D I A The Identity of Everything Co-reference and collocation  Grounding singles out referents and enables co-reference – between speaker and listener – across a sequence of utterances  In Topic Maps the central objective is collocation – By definition, each topic represents a single subject (one subject per topic) – A topic is intended to be a point of collocation for everything that is known about a particular subject – Therefore the goal is to have only one topic per subject  To achieve that we need to know which subject a topic represents – (This is sometimes referred to as the “intentionality” of the relation between a symbol and its referent. – We call it subject identity.
  • 41. www.ontopedia.net O N T O P E D I A The Identity of Everything Subject identity  The identity of a subject is expressed using globally unique identifiers called subject identifiers – If two topics share a subject identifier, they are deemed to represent the same subject and must be merged SUBJECTS TOPICS Madame Butterfly Tosca Lucca Puccini
  • 42. www.ontopedia.net O N T O P E D I A The Identity of Everything The subject is identified by a URL • The URL is called a subject identifier Subject identifiers Giacomo Puccini topic http://psi.ontopedia.net/Giacomo_Puccini subject identifier The URL is the address of a web page • The web page describes the subject such that a human can know what subject is referred to • This web page is called a subject descriptor Giacomo Puccini Italian composer, b. Lucca 22nd Dec 1858, d. Brussels, 29th Nov 1924. Best known for his operas, of which Tosca is one of the most popular and well-known. subject descriptor http://psi.ontopedia.net/Giacomo_Puccini Humans use the descriptor By inspecting the web page the person responsible for assigning the identifier can be sure that it does not refer to, say, Giacomo’s grandfather Domenico (who was also a composer of operas) Machines use the identifier The link is not resolved. Instead simple lexical comparison is used. If the strings are identical, the subject is deemed to be the same and the topics are merged. subject Is the subject identifier/ subject descriptor pairing a symbolic assembly?
  • 43. www.ontopedia.net O N T O P E D I A The Identity of Everything Information structure  Intuitive navigation is a key feature of Topic Maps  But what is its cognitive basis? – I claim that it corresponds to the way we think (i.e., associatively) – Can linguistics back up this claim?  topic vs. comment in linguistics (Bussmann, 487) – “Analysis of sentences according to communicative criteria into the topic (what is being talked about) and the comment (what is being said about the topic)” – “Analysis of utterances according to the communicative criteria of given/known information vs. new information” – Cf. theme vs. rheme in Halliday’s functional grammar  Consider our earlier tour of Italian opera...
  • 44. www.ontopedia.net O N T O P E D I A The Identity of Everything Navigation as narrative Giacomo Puccini was a composer. He was born in Lucca in 1858. Lucca is a city, located in Italy. It was the birthplace of Puccini and Catalani. Catalani was a composer who composed 5 operas. He died in Milan. Milan is the home of La Scala, which was the venue for many premiére performances, including that of Madam Butterfly. Madam Butterfly is set in Nagasaki, which is located in Japan. Japan is (also) the setting for Iris, [which is] an opera [which was] composed by Mascagni, who was a pupil of Ponchielli who was (also) the teacher of Puccini... Giacomo Puccini was a composer. He was born in Lucca in 1858. Lucca is a city, located in Italy. It was the birthplace of Puccini and […] Catalani. Catalani was a composer who composed 5 operas. He died in Milan. Milan is the home of La Scala, which was the venue for many premiére performances, including that of Madam Butterfly. Madam Butterfly is set in Nagasaki, which is located in Japan. Japan is (also) the setting for Iris, [which is] an opera [which was] composed by Mascagni, who was a pupil of Ponchielli who was (also) the teacher of Puccini... THEME: new theme continuing theme RHEME: predicate with potential new theme
  • 45. www.ontopedia.net O N T O P E D I A The Identity of Everything “Now! …. That should clear up a few things around here!” Discussion  Questions, comments, corrections? – What have I missed? Where else should I look?  What might linguists contribute? – A better understanding of the nature of roles? – Approaches to representing temporal knowledge? – ...  Can Topic Maps inform linguistics? – After all, it is a technology that captures (some degree of) (some form of) knowledge – It seems to have a reasonable cognitive basis – It emerged through usage (librarians, indexers, etc.) – And last but not least, it works!
  • 46. www.ontopedia.net O N T O P E D I A The Identity of Everything References  Bussman, H. Routledge Dictionary of Language and Linguistics (London 1996)  Frawley, W. Linguistic Semantics (Hillsdale 1992)  Langacker, R. Cognitive Grammar (Oxford 2008)  Pepper, S. Italian Opera Topic Map – http://www.ontopedia.net/ItalianOpera  Pepper, S. “Topic Maps” in Bates, M.J. and Maack, M.N. (eds) Encyclopedia of Library and Information Sciences (CRC Press, forthcoming 2009) – http://www.ontopedia.net/pepper/papers/ELIS-TopicMaps.pdf