Tracing Networks: Ontology-based Software in a Nutshell

Tracing Networks
Ontology-based software application in a Nutshell
Yi Hong
Department of Computer Science
University of Leicester

Semantic Web
2
Tracing Networks programme
“Semantic web is an evolution to the current web and provide new information representation feature.”
Current web
Document-centric
Human readers
Syntax (Schema)
HTML, XML etc.
Semantic web
Knowledge representation
Machine readable
Semantics (Ontology)
RDF, OWL etc

Ontology
3
What is an ontology?
“An ontology is a formal specification of a conceptualization”
-Thomas Gruber
Describes
Specified by
Ontology
Concepts
Domain
Modelled by
Domain ontology
e.g. (CIDOC-CRM for archaeology, Gene, GXO for Genetics)

Ontology-based database
What is an ontology-based database.
How it is different from a relational database.
Why use ontology? What can you do with an ontology-based database.
How to query an ontology-based database.
4

Relational database vs Ontology-based database
Image on a ceramic vessel found at Sopron-Várhely
5
Example : Image tagging and search for human representation database
(provided by Katharina)

6
Data structure
Object ID: 15
Inventory number: 443
Excavation site: Sopron-Várhely(N47.66519, E16.518044 Hungary)
Human figure (individuals)
rider
wagon guide
wagon rider
Animal
2 horses
1 horse
Material:
ceramic
Technology:
Incised
`
etc.
……….
(60+ attributes)

7
Relational database (MS Access 2007)
tables, fields (columns)
primary-foreign
key pairs
Database schema
Entity-relationship diagram
Data
Data

Relational vs Ontology-based database
Data storage
Ontology
(class, property, individual)
Data Structure
Database Schema
(table, field, key)
records
triples (RDF graph)
Basic elements
Ontology-based Database (Triple store)
Relational Database
Database
products
MySQL, Oracle, SQL Server,
MS Access etc
Jena SDB, virtuoso universal server, RDF/OWL document
8

Ontology
Semantics
Class
Property
Individual
9
individual
has value for
is instance of
class
property
restrict

Ontology
Ontology example:
Class
Person
Archaeologist
Property
Is a friend of
subClassOf
instanceOf
Individual
Alex
John
10

Ontology
A Triple is:
Basic element in the ontology world.
contains three parts: subject, predicate and object.
Predicate
Subject
Object

Ontology
A Triple is:
Basic element in the ontology world.
contains three parts: subject, predicate and object.
was found in
Leicester
Ceramic pot

Ontology
RDF Graph
A set of triples become a graph
An ontology-based database is a graph
was found in
Leicester
Ceramic pot

Ontology
(Protégé Ontology Editor)
Country
Material
…….
isLocatedIn
wasMadeFrom
wasFoundAt
Site
……s.
…….
Object
Appears On
Animal
hasScene
contains
…….
subClassOf
Appears On
Scene
Horse
Appears On
IndividualFigure
http://protege.stanford.edu/
14

Relational vs Ontology-based database
Search
Graph pattern
Text-based keywords+ options
Query
Interface
generate
generate
Query
language
SPARQL
SQL
query
query
Ontology-based Database (Triple store)
Relational Database
Database
15

Why use ontology?
16
Problem with traditional keyword search
Tags: cat , mouse,

Why use ontology?
17
Ambiguous semantics
What you are looking for …..
A tag is normally a freely-chosen, non-hierarchical keyword or term.
The tag can be the identical but it might have different interpretation.
Tags: cat , mouse,

Why use ontology?
18
Ambiguous semantics
The meaning of the keyword is unclear
What you actually get…
Tags: cat , mouse,
(Can not tell what it is about by only looking at the tags… )

Why use ontology?
19
Labelling objects rather than relationship
the keyword approach is more focus on
labeling objects rather than the relationship
Not way to describe the links (chasing)
between them.
Describing the link between objects is as
important as tagging the objects themselves
Tags: cat , mouse,

Why use ontology?
20
Labelling objects rather than relationship
Additional tags will not be sufficient to
describe the links. By adding the third
tag “chase”.
The question remains :
Who is chasing who?
Tags: cat , mouse, chase

Why use ontology?
21
Difficult to describe complex and arbitrary query
rider
Query:
“Display images with an animal and a person on them, along with what is happening between them"
horse

Why use ontology?
22
Query: “Display images with an animal and a person on them, along with what is happening between them"
How to describe this search in a query
interface?
What else?
Library style?
Native SQL?
Google style?
Textbox with drop
down list or check box
SQL syntax
single textbox
Learn complex syntax
Knowledge of DB schema
Difficult to write
Not expressive enough
Not flexible enough

Why use ontology?
23
Unable to perform automatic reasoning
Problems 1
Ask for : person, animal
Actual tags: rider, horse
Traditional search engine is based on keyword match. the tags we have here are rider and horse, if it does not contain any keywords we entered, the search engine will not return anything
It needs background knowledge to understand a rider is a person riding a horse and a horse is in fact an animal.
rider
horse

Why use ontology?
Single user Mode vs Collaborative Mode
Degree of uncertainty
User credibility and expertise
Degree of uncertainty = CF
Domain-specific expertise index = E(d)
probably a fox ?
definitely a horse!
Is a
zoologist
5 year kid
horse
Tagged area
95%
24

Query results visualisation-Geo-mapping
Keyhole Markup Language (KML/KMZ)
http://code.google.co m/apis/kml/documentation/
XML-based language.
Supports place marks, images, polygons, 3D models, textual descriptions
Compatibility
Google Map
Google Maps for Mobile
Google Earth
ESRI ArcGIS Explorer,
25

Query results visualisation- Statistical charts
Google Chart API
http://code.google.com/apis/chart/
Interactive Flash
Javascript arrays or XML files
Compatibility
Most mainstream browsers
Internet Explorer
Firefox
Safari
Chrome
26

27
Ontology-based software demo
Semantic tagging
Query by graph pattern
Integration with Google earth
Statistical charts

System Architecture
28

Links
A Guide to Creating Your First Ontology
By Stanford University
http://www.ksl.stanford.edu/people/dlm/papers/ontology-tutorial-noy-mcguinness-abstract.html
Protégé Ontology editor
http://protege.stanford.edu/
Protégé tutorial http://owl.cs.manchester.ac.uk/tutorials/protegeowltutorial/
CIDOC-CRM ontology
An ontology for culture and heritage domain
http://www.cidoc-crm.org/
KML guide and tutorial
http://code.google.com/apis/kml/documentation/kml_tut.html
29

http://www.tracingnetworks.ac.uk	164
http://www.tracingnetworks.org	59
http://tracingnetworks.ac.uk	14
http://www.digitalhistory.graeworks.net	7
https://twimg0-a.akamaihd.net	1

Tracing Networks: Ontology-based Software in a Nutshell

by TracingNetworks on Apr 05, 2011

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