Knowledge Retrieval on the World Wide Web

The WebKB set of tools

Philippe A. MARTIN

(e-mail: pm .@. phmartin dot info)

Griffith University, School of Information Technology

Work supported by the Defence Science And Technology Organisation (DSTO)

Copyright © Philippe A. Martin · Last update: 26 March 1999 · e-mail: pm .@. phmartin dot info   Next


Knowledge: data representations supporting logical inferences and semantic queries

KRLs / XML-based Metadata Languages

XML-based metadata languages require special editors
and generally do not yet have facilities for logic-based representation

Representation of "John believes that Mary has a cousin who has the same age as her"
in Formalised English, Frame-CGs, CGs, KIF and RDF

Formalised English with undeclared terms

<KR language="FE"> {Mary has for cousin a person who has for chrc an age chrc of Mary}(Believer:John). </KR> <KR language="FE"> John believes {Mary has for age A and has for cousin a person who has for age A}. </KR>

Frame-CGs with undeclared terms

<KR language="CG"> [Mary; chrc: [an age *a], cousin: [a person; chrc:*a]; ](Believer: John). </KR>

CGs with declared terms

<KR language="CG"> load ""; Age < Property; Cousin(Person,Person) {Relation type Cousin}; [Statement: [Person: "Mary"]- { ->(Chrc)->[Age: *a]; ->(Cousin)->[Person]->(Chrc)->[*a]; } ]->(Believer)->[Person: "John"]; </KR>


<KR language="KIF"> load ""; (Define-Ontology Example (Slot-Constraint-Sugar topLevelOntology)) (Define-Class Age (?X) :Def (Property ?X)) (Define-Relation Cousin(?s ?p) "Relation type Cousin" :Def (And (Person ?s) (Person ?p))) (Exists ((?j Person)) (And (Name ?j John) (Believer ?j '(Exists ((?m Person) (?p Person) (?a Age)) (And (Name ?m Mary) (Chrc ?m ?a) (Cousin ?m ?p) (Chrc ?p ?a) )) ))) </KR>


<!-- RDF notation (with allowed abbreviations) --> <RDF xmlns="" xmlns:t=""> <Class ID="Age"> <subClassOf resource="t#Property"/> </Class> <PropertyType ID="Cousin"> <comment>Relation type Cousin</comment> <range resource="t:Person"/> <domain resource="t:Person"/> </PropertyType> </RDF> <RDF xmlns="" xmlns:t="" xmlns:x=""> <Description aboutEach="#Statement_01"> <t:Believer>John</t:Believer> </Description> <t:Person bagID="Statement_01"> <t:Name>Mary</t:Name> <t:Chrc><x:Age ID="age"></x:Age></t:Chrc> <x:Cousin><t:Person><t:Chrc resource="#age"/></x:Cousin> </t:Person> </RDF>


  • WWW-accessible knowledge processor (CGI server)

  • Graphical interfaces: Netscape + Javascript

  • Predefined ontologies (in HTML documents)



  • Scalable multi-user persistent object repository

  • Algorithms for exploitating large-scale dynamic taxonomies

  • Visualisation techniques (generation of views, aliases)

  • Protocols to allow users to solve semantic conflicts

  • Conventions for representing knowledge

ICCS'98 slides, VirtualDoc slides