And Coolheads Consulting A Processing Model for Topic Maps Knowledge Technologies 2001 Austin, 6...

andandCoolheads Coolheads ConsultingConsulting

A Processing A Processing Model Model

for Topic Mapsfor Topic Maps

Knowledge Technologies 2001Austin, 6 March 2001

Steven R. Newcomb ([email protected])Michel Biezunski ([email protected])

© 2001, InfoLoom, Inc. and Coolheads Consulting. All rights reserved.



Syntax is only half of Syntax is only half of the storythe story

• Syntax is for interchange.• Interchange Syntax is not enough

for processing. Need an explicit processing model to describe what the result of processing is.

• XML technology is useful but not sufficient for topic map processing.

• Implementers must know the processing model in order to build interoperable applications.




What is a topic map?What is a topic map?

• The answer you get depends on whom you ask.

• This situation is inconsistent with the use of topic maps for global knowledge interchange.

• Typical answers:– A kind of XML document, right?– A finding aid made from an XML

document by a process of rendition…?– Whatever application X thinks a

<topicMap> element means…?




Topic Map paradigm: Topic Map paradigm: Historical FactsHistorical Facts

• The entire history was driven by idealists interested in solving the central problems of information management.

• 1993: First expression of Topic Map paradigm in Davenport SOFABED draft by Steven R. Newcomb. “Syntactically, topics are best represented as independent links!”





• 1993: Schism of Davenport Group project into– DocBook. (That’s another story.)– Conventions for the Application

of HyTime (CApH), hosted by GCA Research Institute (now IDEAlliance), chaired by Steven R. Newcomb.





• 1993-1995: Several CApH drafts of topic map syntax and description, as a HyTime-conforming “Architecture Definition Document”.





• 1995-1997: Michel Biezunski as pioneering hero of the Topic Map story– makes first implementations; – proves the value of the topic

maps paradigm;– popularizes the paradigm;– serves the needs of real

customers.





• 1997: Steve Newcomb and Michel Biezunski start working together again. With Martin Bryan, they become co-editors of ISO/IEC 13250.

• 1997: Peter Newcomb asks, “What’s the model?” Steve and Michel say, “What do you mean, ‘What’s the model?’?”





• 1997: Vicky Newcomb and Peter Newcomb eat tacos for breakfast at the Plano, Texas Whataburger. The model later known as “binding points” and “Whataburger” is born.





• 1998: Bryan Bell pays Steve and Michel to be locked in a room in Tacoma until they finish drafting ISO/IEC 13250.





• Essential Dialectic Tension: – Biezunski’s Principle vs. – Newcombian incomprehensible

elegance.

• Result: ISO/IEC 13250, with no explicit processing model, but total compatibility with Whataburger. Whataburger remains largely undisclosed, in the interests of getting the standard adopted.





• 2000: ISO/IEC 13250:2000 finally, at last, adopted by ISO. It’s based on SGML and HyTime.





• GCA IDEAlliance (Dianne Kennedy, Paul Conn, etc.) prevails upon Michel and Steve to head up a new standards effort to make an XML Specification for Topic Maps as quickly as possible, in order to launch industries based on topic maps for the Web.

• Can we get the Whataburger model published and standardized at last?




What you need to know What you need to know

1. A topic is a surrogate for a subject. 2. Subjects can be either indicated or

constituted by resources.3. Topics have characteristics: names,

occurrences, and associations with other topics.

4. Topic characteristics are applicable within defined scopes.

5. Two rules govern the merging of topic maps: the subject-based and the name-based merging rules.




A Topic Map Processing A Topic Map Processing ModelModel

• Node types– t-node– a-node– s-node

• Arc types– association member– association scope– association template– scope component

• Topic-ification of resources




What is a topic map?What is a topic map?

Interchangeable topic map

XML <topicmap> elements conforming to a structure defined by the XTM DTD.

Interpreted topic map

Application-internal graph resulting from processing the syntax. The topic map graph exhibits unambiguously all properties of topic map constructs.

Formatted topic map

Examples: HTML rendering of a topic map as an index; printed index.




What is a Topic?What is a Topic?

• The computer representation of a subject (element or node)

• A set of topic characteristics:– topic names– topic occurrences– memberships of topics in

associations




Topic Map GraphTopic Map Graph

• A set of nodes: t-nodes, a-nodes, and s-nodes.

SS

TT TT

AATT

TT TT

TT




Subjects and TopicsSubjects and Topics

• Subjects are notions.• Topics are computer

constructs.• Topics are surrogates

for subjects.

subject

topic




Topics have two Topics have two aspectsaspects

1. Syntactical, interchangeable elements<topic ... > ... </topic>

2. Application-internal nodes (t-nodes)

TT TTAA TT

TT TTTT SS




When two topics have When two topics have the same subject...the same subject...

topic topic

...Topics get merged into one t-node in the topic map graph.

TT

T

subject




Subjects and resourcesSubjects and resources

• An information resource can indicate what the subject is,

and/or

• an information resource can be the subject.subject

subject




Addressability of Addressability of SubjectsSubjects

• Subject is not addressable

or

• Subject is addressable

subject

subject




Subject Referencing Subject Referencing SyntaxSyntax

<subjectIndicatorRef>

<resourceRef>subject

subject




The Subject Identity The Subject Identity PointPoint

• Each subject can be considered a hub connecting all topics having this subject.

• Such a hub, called a "subject identity point", is a resource that either constitutes or indicates a subject.

• Therefore all <topic>s which refer to the same subject are to be considered the same topic.




Two Forms of Two Forms of AssociationsAssociations

• Associations are computer constructs that take two forms:– Syntactic, interchangeable

associations<association> .... </association>– Application-internal associations (a-

nodes)

TT TT

AA




Associations and Associations and TopicsTopics

• Associations connect topics

• Associations can be considered as topics.

TT TT

AA

TAA




Topic NameTopic Name

• Base Name: Name used to designate a topic.

• A topic may have zero, one, or several base names.

• A base name can be explicitly scoped.

• Each base name can have several variants, for various processes (display, audible rendition, sort, ...)




Topic-basename Topic-basename AssociationsAssociations

• The base name becomes a topic whose subject is the string resource that is the base name.

• A topic-basename association connects the named topic to its name, within some scope.




Basename-variantname Basename-variantname AssociationsAssociations

• The variant name becomes a topic whose subject is the information resource that is the variant name.

• A basename-variantname association connects the variant to the topic-basename association




ScopesScopes

• Topic characteristics have scopes.

• A scope is an extent of validity.

• A scope is represented as a set of topics.




Topic namespacesTopic namespaces

• Scopes are used to define namespaces for topics.

• TOPIC NAMING CONSTRAINT: No two topics can have the same name in the same scope (i.e., the same topic namespace).

• (This has absolutely nothing to do with "XML Namespaces".)




What gets scopedWhat gets scoped

• Scope applies to topic characteristics:– name,– occurrence,– role played in relation with other

topics.

• Topics do not have scope. Only topic characteristics have scope.




OccurrenceOccurrence

• Information resource attached to the topic because it is relevant to the subject that the topic represents.




Topic-occurrence Topic-occurrence AssociationsAssociations

• The occurrence becomes a topic whose subject is the resource that is the occurrence.

• A topic-occurrence association connects the named topic to its occurrence, within some scope.




More...More...

• http://www.topicmaps.net, a web site maintained by Michel Biezunski and Steven R. Newcomb.

And Coolheads Consulting A Processing Model for Topic Maps Knowledge Technologies 2001 Austin, 6...

Documents

Transcript of And Coolheads Consulting A Processing Model for Topic Maps Knowledge Technologies 2001 Austin, 6...