presented by: yuhana 12/17/2007 context aware group - intelligent agent laboratory computer science...

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


Insert the keyword about Physiotherapy Centre Find the information about physiotherapy

center that ◦ near his home or office◦ support assurance◦ Match with his calendar



Drawback: Find link to physiotherapy

center websites in few second but consuming time to find match information


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


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


OWL

XML

RDF & RDFS

OWL


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


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 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


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


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


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


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

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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

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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

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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

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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.

presented by: yuhana 12/17/2007 context aware group - intelligent agent laboratory computer science...

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