Hartwig Hochmair 1

Hartwig Hochmair

Institute for Geoinformation

TU Vienna

Revigis meeting Carnuntum 2001

Data Sources Used for the Navigation Process in the web

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Outline

• Idea of my model for WWW navigation• Two data sources for WWW navigation• In which realms of WWW navigation plays

semantic matching a role

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Model: 2 data sourceswww

use similarities of concepts for web navigation

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Structure of web domain• Vertical categories with subcategories• Crosslinks (dashed)• one single graph

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User’s View: Aristotle’s Ontology

object

things bodies qualities events processes

substance accident

affordance

[Gibson, 1977]

attributes action affordancesphysical objecthierarchy

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Structure of the Semantic Map

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Three Levels of Matching

1. web browser interface (interface level): • advertised and afforded actions • meaning of symbols• meaning of technical terms

2. synonymy of perceived terms (context-level)

3. view of the world of web designer and web user (ontology level)

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1. Interface Level

• B.Smith (1999): “In the world of information systems,…ontology is constituted by a specific vocabulary and programming environment”

• ontological engineers philosopher-ontologists

• languages• descriptions• software representations• representation in people’s mind

• objects• properties• states• events• processes

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1. Technical Terms

• B.Smith (1999): “In the world of information systems,…ontology is constituted by a specific vocabulary and programming environment”

• ontological engineers philosopher-ontologists

• independent of language• software artifact• for specific use• computational environment

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1. specific vocabulary for scientific domain

• Refresh• Home• Favorites• Discuss• Sychronize…

• Symbols:

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1. specific vocabulary for scientific domain

• Refresh• Home• Favorites• Discuss• Sychronize…

• Symbols:

Assumed as Common knowledge –not to be expclicitely modeled

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2. Context Level

• One term has several meanings (polysemous terms)

• User-defined template: filled by information [Guarino 97]

• Template provides context

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2. Example for Semantic Matching

Red(X)

this shirt is red (colour)a politician is a red (political direction)

an Indian is a red (human race)

in WWW navigation: clear through context

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3. Ontology and Epistemology

• …the science of what is, of the kinds and structures of the objects, properties and relations in every area of reality [Smith 99]

• WWW: 2 different ‘ontologies’– existing web structure (fact): ontology– user’s mental map (belief): epistemology

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3. Overlap of Ontology and Epistemology

All

User

DesignerUD

disjoint Area

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3. Example for Successful Data Matching

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3. Potential Problems (www)

Error in web design: not designed for various user groups

No absolutely ‘correct ontology’ => differences between web ontology (web designer) and web user.

For example: caused by inconsistent subset relations in the web structure

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missing inconsistency:

clothing

shoe

where is link ‘shoe’ ??user gets lost!

clothing shoe

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Conclusions

• Different levels of semantic matching applied in WWW navigation

• Problem: different ontology/epistemology• 2 main data sources

– different structure– represent same content

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Kinds of Ontologies

[Guarino 1997]

top-level ontology

domain ontology task-ontology

application ontology

(sem. matching,Smith 1999)

(symbols, similar voca-bulary, functions)