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Presented by:Yuhana
12/17/2007
Context Aware Group - Intelligent Agent LaboratoryComputer Science and Information Engineering
National Taiwan University (NTU)
12/17/2007◦ Idea of Ontology◦ Semantic Web Vision◦ For Today’s Web to The Semantic Web◦ The advantage of Ontology◦ Ontology in a glance
Next Week -- 12/24/2007◦ Introduction to OWL(OWL, RDF, N3)◦ Create and Build Ontology using Protégé
Person
CarhasCar
hasFirstName
hasBirthDate
William
MercedeshasCar
hasFirstName
hasBirthDate
Class
Instance
Relationship/Property
Class
Date
String
“John”
2/20/1967
Instance
To make a number of applications more capable of handling complex and disparate information
To make Semantic Web Vision comes true
Idea of Ontology
Evolving extension of WWW in which web content : ◦ Can be expressed not only in natural language◦ But also can be understood, interpreted and used
by software agents◦ Permitting software agents to find, share and
integrate information easily The idea of having data on the Web
◦ Defined and linked in such a way◦ Can be used by machines not only for display
purposes, but for automation, integration and reuse of data across various applications
Semantic Web Vision
Semantic Web Layer Cake
Semantic Web Vision
• William had just had a minor car accident and was feeling some neck pain.
• He wants to find and go to Physiotherapy Centre for physical therapy sessions.
• How today’s web can help ?• How with semantic web ?
From Today’s Web to The Semantic Web
Near his home or office Support assurance Open in holiday or match
with his calendar
From Today’s Web to The Semantic Web
Insert the keyword about Physiotherapy Centre Find the information about physiotherapy
center that ◦ near his home or office◦ support assurance◦ Match with his calendar
From Today’s Web to The Semantic Web
From Today’s Web to The Semantic Web
Drawback: Find link to physiotherapy
center websites in few second but consuming time to find match information
From Today’s Web to The Semantic Web
Doctor agent
Insurance agent
location agent
Calendar agent
Rating agent
1. machine readable2. the carriers of the meaning
contained in the Semantic Web 3. provide the vocabulary and
semantics of the annotations
Ontologies are the key to the Semantic Web
From Today’s Web to The Semantic Web
Knowledge/information representation◦ Create a database schema / structure◦ Map the schema to an upper ontology
For taxonomic(class) reasoning Support description logical reasoning
◦ After reasoning we can get new knowledge
Advantage of Ontology
Kind of things that actually exist, and how to describe them -> philosophy term
In computer science :◦ Explicit and formal specification of a
conceptualization◦ Consist of finite list of terms and the relationships
between these terms Consist of concepts (also knowns as
classes), relations (properties), instances and axioms (CRIA)
Ontology in a Glance
Person
Location
hasLocation
hasFirstName
hasBirthDate
Date
String
Physiotherapy Centre
hasLocation
Float
Float
hasLongitute
hasLatitude
Ontology in a Glance
OWL
XML
RDF & RDFS
OWL
Ontology in a Glance
To Share common understanding of the structure of information among people or software agents
To enable reuse of domain knowledge To make domain assumptions explicit To separate domain knowledge from the
operational knowledge
Ontology in a Glance
http://xml.com/2002/11/06/Ontology_Editor_Survey.html
Popular editor tools:◦ Protégé (editor, open source, plug in, Inference
Engine, API)◦ Ontopia Knowledge Suite (OKS) (editor, open
source, plug in, Inference Engine, API)
Ontology in a Glance
Ontology is not always the only one tool for the job, it should be collaborate with another technology
Face recognition – not the right applications for ontology
Ontology in a Glance
An attempt to capture the most general and reusable terms and definitions
In another word, we can say upper ontology as top-level ontology, or foundation ontology that an attempt to create an ontology which describes very general concepts that are the same across all domains
Ontology in a Glance
DOLCE (Descriptive Ontology for Linguistic and Cognitive Engineering)
Cyc SUMO (Suggested Upper Merged Ontology) Basic Formal Ontology(BFO) General Formal Ontology (GFO) Wordnet Biomedical Ontology
Ontology in a Glance
Ontologies may have different names for the same things◦ type – a relation between a class and an instance◦ instance – a relation between a class and an
instance◦ isa – a relation between a class and an instance◦ …
Ontologies may have the same name for different things, and no corresponding terms
Either use the same upper ontology, or at least map to a common upper ontology
Ontology in a Glance
Ontology in a Glance
Next Week -- 12/24/2007◦ Introduction to OWL(OWL, RDF, N3)◦ Create and Build Ontology using Protege
Suggestion Steps◦ Paper reading:
http://www.w3.org/TR/owl-ref/ N.F Noy, and D.L. McGuinnes, Ontology Development 101 : A
Guide to Creating Your First Ontology, 2001 Chapter 7 A Semantic Web Primer Book About Ontology
Engineering Learn Protege-OWL by going over the Protege-OWL tutorial
http://protege.stanford.edu/overview/protege-owl.html◦ Download & install Protégé 3.4 (
http://protege.stanford.edu/)
Grigoris Antoniou and Frank van Harmelen , Semantic Web Primer Book, The MIT Press, 2004
http://www.w3.org/DesignIssues/Semantic.html
http://www.xml.com/pub/a/2002/11/06/ontologies.html?page=2
HTML
XML
30
HTML stand for Hyper Text Markup Language
An HTML file is a text file containing small markup tags
The markup tags tell the Web Browser how to display the page
An HTML file must have an htm or html file extension
An HTML file can be created using a simple text editor
31
XML stands for EXtensible Markup Language XML is a markup language much like HTML XML was designed to describe data XML tags are not predefined. We must
define our own tags XML uses a Document Type Definition
(DTD) or an XML Schema to describe the data
XML with a DTD or XML Schema is designed to be self-descriptive
XML is a W3C Recommendation
33
Uniform Resource Identifier Every resource has URI Resource : “thing” we want to talk about
(e.g. authors, lectures, books, etc) URI can be URL (Uniform Resource Locator
or web address) or some other kind of unique identifier
In general, assume that URI is the identifier of a web resource
34
Resource (Subject)
Resource
URI
Every Resource has URI
Resource
is an artificial intelligence project that attempts to assemble a comprehensive ontology and database of everyday common sense knowledge, with the goal of enabling AI applications to perform human-like reasoning.