languages for semantic web

Languages for Semantic Languages for Semantic WebWeb葉慶隆葉慶隆

大同大學資訊工程系所大同大學資訊工程系所Email: [email protected]

URL: www.cse.ttu.edu.tw/chingyeh

Languages for Semantic Web 2

Sources

• Knowledge Markup and Resource Semantics, By Harold Boley, Stefan Decker, and Michael Sintek, IJCAI-01 Tutorial, http://www.ijcai-01.org/

• XML Fundamentals, http://www.ibiblio.org/xml/slides/sd2001east/fundamentals/XML_Fundamentals.html

• Anupriya Ankolenkar, et al., “DAML-S: Semantic Markup For Web Services,”, Proceedings of SWWS’ 01, the First Semantic Web Working Symposium, California, USA, July 30 - August 1, 2001.


Overview• Increasing demand

for formalized knowledge on the Web: AI’s chance!

• XML- & RDF-based markup languages provide a 'universal' storage/interchange format for such Web-distributed knowledge representation

• In this talk, we focus on Semantic Web languages: XML, RDF(S), DAML.

DTDs

XML

RDF[S]

Namespaces

Stylesheets

CSS

XSLT

XQL

Queries

XML-QL

Transformations

Acquisition

Protégé

Agents

Frames

Rules

SHOE

HornML

RuleML

DAML

XQuery

TopicMaps

Ontobroker


Web Languages forKnowledge Capturing

• Human knowledge is (partially) captured on the Web as informal texts, semiformal documents, and structured metadata

• Each kind of knowledge has its (preferred) markup language

Knowledgeinforma

lSemiform

alMetadat

a

Language HTML XML RDF


Web Languages forMachine Interpretation

• XML (Extensible Markup Language): Semiformal documents range between non-formatted texts and fully formatted databases

• RDF (Resource Description Framework): Structured metadata describe arbitrary heterogeneous Web pages/objects in a homogeneous manner.

Machines (e.g. search engines) can analyzeXML or RDF markups better than full HTML


The Semantic Web Activityof the W3C

“The Semantic Web is a vision: the idea of havingdata on the Web defined and linked in a way thatit can be used by machines not just for display purposes,but for

• automation,• integration and• reuse of data across various applications.”

(http://www.w3.org/2001/sw/Activity)


The Semantic Web Layered Architecture

(http://www.w3.org/2001/Talks/0228-tbl/slide5-0.html)

Tim Berners-Lee:“Axioms, Architecture and Aspirations”W3C all-working group plenary Meeting28 February 2001

XML Fundamentals

Source: http://www.ibiblio.org/xml/slides/sd2001east/fundamentals/XML_Fundamentals.html


What is XML?

• Extensible Markup Language• A syntax for documents • A Meta-Markup Language• A Structural and Semantic language, not a

formatting language• Not just for Web pages


Extensible Markup Language

• Language – It has a grammar– It has a vocabulary (sort of)– It can be parsed by machines

• Markup Language– It says what things are; not what they do– It is not a programming language– It is not compiled

• Extensible – You can add words to the language


XML is a Meta Markup Language

• Not like HTML, troff, LaTeX• Make up the tags you need as you need them• The tags you create can be documented in a Docu

ment Type Definition (DTD)• A meta syntax for domain-specific markup languag

es like MusicML, MathML, and XHTML


XML Applications

• A specific markup language that uses the XML meta-syntax is called an XML application

• Different XML applications have their own more constricted syntaxes and vocabularies within the broader XML syntax

• Further syntax can be layered on top of this; e.g. data typing through schemas


XML describes structure and semantics, not formatting

• XML documents form a tree– Document Object Model (DOM)

• Element and attribute names reflect the kind of the element– DTD, Schema

• Formatting can be added with a style sheet– Cascading Style Sheets (CSS)– Extensible Stylesheet language (XSL)


XML Hypertext

• A Uniform Resource Identifier (URI) names or locates a resource

• An XLink defines connections between two or more documents identified by URIs

• XPath identifies particular nodes within a document

• An XPointer adds an XPath to a URI• XBase defines the URI against which relative URIs a

re resolved • XInclude embeds a document identified by a URI in

side an XML document.


A Song Description in HTML

<dt>Hot Cop<dd> by Jacques Morali, Henri Belolo, and Victor Willis<ul><li>Producer: Jacques Morali<li>Publisher: PolyGram Records<li>Length: 6:20<li>Written: 1978<li>Artist: Village People</ul>


A Song Description in XML

<SONG> <TITLE>Hot Cop</TITLE> <COMPOSER>Jacques Morali</COMPOSER> <COMPOSER>Henri Belolo</COMPOSER> <COMPOSER>Victor Willis</COMPOSER> <PRODUCER>Jacques Morali</PRODUCER> <PUBLISHER>PolyGram Records</PUBLISHER> <LENGTH>6:20</LENGTH> <YEAR>1978</YEAR> <ARTIST>Village People</ARTIST></SONG>


Style Sheets Provide Formatting(CSS)

SONG {display: block; font-family: New York, Times New Roman, serif}TITLE {display: block; font-size: 24pt; font-weight: bold; font-family: Helvetica, sans}COMPOSER {display: block}PRODUCER {display: block}YEAR {display: block}PUBLISHER {display: block}LENGTH {display: block}ARTIST {display: block; font-style: italic}


Attaching Style Sheets to Documents

<?xml-stylesheet type="text/css" href="song.css"?><SONG> <TITLE>Hot Cop</TITLE> <COMPOSER>Jacques Morali</COMPOSER> <COMPOSER>Henri Belolo</COMPOSER> <COMPOSER>Victor Willis</COMPOSER> <PRODUCER>Jacques Morali</PRODUCER> <PUBLISHER>PolyGram Records</PUBLISHER> <LENGTH>6:20</LENGTH> <YEAR>1978</YEAR> <ARTIST>Village People</ARTIST></SONG>


An XSLT Stylesheet (Part 1)

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

<xsl:template match="/"> <html> <head><title>Song</title></head> <body> <xsl:apply-templates select="SONG"/> </body> </html> </xsl:template>


An XSLT Stylesheet (Part 2) <xsl:template match="SONG"> <h1> <xsl:value-of select="TITLE"/> by the <xsl:value-of select="ARTIST"/> </h1> <ul> <li>Length: <xsl:value-of select="LENGTH"/></li> <li>Producer: <xsl:value-of select="PRODUCER"/></li> <li>Publisher: <xsl:value-of select="PUBLISHER"/></li> <li>Year: <xsl:value-of select="YEAR"/></li> <xsl:apply-templates select="COMPOSER"/> </ul> </xsl:template>

<xsl:template match="COMPOSER"> <li>Composer: <xsl:value-of select="."/></li> </xsl:template></xsl:stylesheet>


Transforming the Document<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <title>Song</title> </head> <body> <h1>Hot Cop by the Village People </h1> <ul> <li>Length: 6:20</li> <li>Producer: Jacques Morali</li> <li>Publisher: PolyGram Records</li> <li>Year: 1978</li> <li>Composer: Jacques Morali</li> <li>Composer: Henri Belolo</li> <li>Composer: Victor Willis</li> </ul> </body></html>

XSLT Processor

(IE 5)

XSL document(template rules)

XML document

Output

A DTD for Songs

<!ELEMENT SONG (TITLE, COMPOSER+, PRODUCER*, PUBLISHER*, LENGTH?, YEAR?, ARTIST+)>

<!ELEMENT TITLE (#PCDATA)>

<!ELEMENT COMPOSER (#PCDATA)><!ELEMENT PRODUCER (#PCDATA)><!ELEMENT PUBLISHER (#PCDATA)><!ELEMENT LENGTH (#PCDATA)><!ELEMENT YEAR (#PCDATA)>

<!ELEMENT ARTIST (#PCDATA)>


Well-formedness

• Rules:– Open and close all tags– Empty tags end with />– There is a unique root element– Elements may not overlap– Attribute values are quoted– < and & are only used to start tags and entities– Only the five predefined entity references are used– Plus more...


Validity

• To be valid an XML document must be1. Well-formed2. Must have a Document Type Definition

(DTD)3. Must comply with the constraints specified

in the DTD


What Is XML Used for?

• Domain-Specific Markup Languages– XML in industrial applications: http://www.xml.org/xml/in

dustry_industrysectors.jsp• Self-Describing Data

– Much data is lost due to format problems.• Interchange of Data Among Applications

– Electronic business: RosettaNet, ebXML


XML Namespaces• XML namespaces are akin to namespaces,

packages, and modules in programming languages

• Disambiguation of tag–and attribute–names from different XML applications (“spaces”) through different prefixes

• A prefix is separated from the local name by a “:”, obtaining prefix:name tags

• Namespaces constitute a layer on top of XML 1.0, since prefix:name is again a valid tag name and namespace bindings are ignored by some tools


Namespace Bindings

• Prefixes are bound to namespace URIs by attaching an xmlns:prefix attribute to the prefixed

element or one of its ancestors, prefix:name1 ,...,

prefix:namen

• The value of the xmlns:prefix attribute is a URI, which may or (unlike for DTDs!) may not point to a description of the namespace’s syntax

• An element can use bindings for multiple name-

spaces via attributes xmlns:prefix1 ,...,

xmlns:prefixm


Two-Namespace Example: Snail-Mail and Telecoms Address Parts

<mail:address xmlns:mail="http://www.deutschepost.de/" xmlns:tele="http://www.telekom.de/"> <mail:name>Xaver M. Linde</mail:name> <mail:street>Wikingerufer 7</mail:street> <mail:town>10555 Berlin</mail:town> <mail:bill>12.50</mail:bill> <tele:phone>030/1234567</tele:phone> <tele:phone>030/1234568</tele:phone> <tele:fax>030/1234569</tele:fax> <tele:bill>76.20</tele:bill></ mail:address>

bill disambiguation through mail and tele prefixes

Resource Description Framework

RDFSource: Knowledge Markup and Resource Semantics,By Harold Boley, Stefan Decker, and Michael Sintek,IJCAI-01 Tutorial, http://www.ijcai-01.org/


Outline

• Motivation: Why XML is not enough

• Introduction to RDF

– Requirements for KR on the Web

– The RDF Data Model

– RDF Schema

• Extensions of RDF(S)

• Tools for RDF and RDF Schema

– Parser, Query, and Inference Engines


Why The Shift Towards More Semantics?

• Information Overload

– Information on the Web currently aiming at Human

Consumption

– Information Consumption is too time consuming

• Search Engines fail more and more

– combined coverage is less than 42% of the HTML-Web

• Data Interchange growing (e.g. B2B)

– needs a common semantics


Extensible Markup Language (XML) Revisited

• Key idea: separate structure from presentation

• XML DTDs or Schemas define document structure

• Replace HTML with two things• A domain specific markup language (defined in XML)

• A map from that markup language to HTML (defined using XSLT)

• DTD enables document recipients to tell whether they’ve received a grammar-conforming document– Gives a minimal level of validation


Why XML is Not Enough

• Main advantage of using XML is reusing the

parser

and document validation

• Many different possibilities to encode a domain

of discourse

• Leads to difficulties when understanding of

foreign documents is required

==> Next step: separate content from structure!


Encoding of Knowledge: Example

http://www.w3.org/Home/Lassila Creator

Endless encoding possibilities in XML:

“The Creator of the Resource “http://www.w3.org/Home/Lassila” is Ora Lassila

Ora Lassila

<Creator> <uri>http://www.w3.org/Home/Lassila</uri> <name>Ora Lassila</name></Creator><Document uri=“http://www.w3.org/Home/Lassila” <Creator>Ora Lassila</Creator></Document>

<Document uri=“http://www.w3.org/Home/Lassila” Creator=“Ora Lassila”/>


Point to Point Communicationfor Machine-Understandable

Data

Translation Step

<xsd:schema xmlns:xsd="http://..."> <xsd:annotation> A-Schema

</xsd:...</xsd:schema>

Conceptual Domain Model(Objects and Relations)

DTD or XML Schema

Deployment

Recipient using DTD A

XML-based Communicationusing DTD A

Sender using DTD A

XML-Parser

Parse Tree

Person is_a Mammal Student is_a Person ----

Common Semantics


Many Previously Unknown Communication Partners


New Partners Don’t Understand Each Other

XML-based Communicationusing DTD A

Sender using DTD A Recipient using DTD A

XML-Parser

Parse Tree

Communication Partner using DTD B

? ?

Communication Partner using DTD C

?


Merging Steps Between Models

<xsd:schema xmlns:xsd="http://..."> <xsd:annotation>A-Schema


<xsd:schema xmlns:xsd="http://..."> <xsd:annotation>B-Schema


<xsl:stylesheet version="1.0” xmlns:xsl="http://....Transform" <xsl:template match="/"> .... </xsl:template></xsl:stylesheet>

<xsl:stylesheet version="1.0” xmlns:xsl="http://....Transform" <xsl:template match="/"> .... </xsl:template></xsl:stylesheet>

Matching

Reengineeringof the conceptual model

XML Document Translation Generation(e.g. in XSLT)

DTD A DTD B

XML Document Translation fromDTD A to DTD B(and B to A)

Steps

Matching


Merging/Aligning Models

• Reengineering step is costly and unnecessary,

when a conceptual language is in use

• Generation document translation procedures is

again complicated and unnecessary

==> use a level on top of XML

• What are requirements for such a level?


Postulates: Fundamental Requirements for KR on the Web

1. Knowledge on the Web is distributed (link Knowledge on the Web)

2. Knowledge on the Web is biased - there is no universal truth it must be possible to dispute statements

3. Many different user communities: Extensibility and Simplicity

==> Resource Description Framework (RDF)


Introduction to RDF• RDF (Resource Description Framework)

– Beyond Machine readable to Machine understandable

• RDF unites a wide variety of stakeholders:– Digital librarians, content-raters, privacy advocates,

B2B industries, AI...– Significant (but less than XML) industrial momentum,

lead by W3C

• RDF consists of two parts– RDF Model (a set of triples)– RDF Syntax (different XML serialization syntaxes)

• RDF Schema for definition of Vocabularies (simple Ontologies) for RDF (and in RDF)


RDF Data Model• Resources

– A resource is a thing you talk about (can reference)– Resources have URI’s– RDF definitions are themselves Resources (linkage,

see requirement 1)

• Properties – slots, define relationships to other resources or atomic

values

• Statements– “Resource has Property with Value”– (Values can be resources or atomic XML data)

• Similar to Frame Systems


A Simple Example• Statement

– “Ora Lassila is the creator of the resource http://www.w3.org/Home/Lassila”

• Structure– Resource (subject) http://www.w3.org/Home/Lassila– Property (predicate) http://www.schema.org/#Creator– Value (object) "Ora Lassila”

• Directed graph

http://www.w3.org/Home/Lassilas:Creator

Ora Lassila


Another Example

• To add properties to Creator, point through an intermediate Resource.

http://www.w3.org/Home/Lassila

s:Creator

Person://fi/654645635

Name

Ora Lassila [email protected]

Email


Collection Containers

• Multiple occurrences of the same PropertyType don’t establish a relation between the values– The Millers own a boat, a bike, and a TV set– The Millers need (a car or a truck)– (Sarah and Bob) bought a new car

• RDF defines three special Resources:– Bag unordered values rdf:Bag

– Sequence ordered values rdf:Seq

– Alternative single value rdf:Alt• Core RDF does not enforce ‘set’ semantics amongst

values


Example: Bag

• The students incourse 6.001 are Amy, Tim,John, Mary,and Sue

Rdf:Bag

/Students/Amy

/Students/Tim

/Students/John

/Students/Mary

/Students/Sue

bagid1

/courses/6.001

students

rdf:type

rdf:_1

rdf:_2

rdf:_3

rdf:_4

rdf:_5


Example: Alternative

• The source code for X11 may be found at ftp.x.org, ftp.cs.purdue.edu, or ftp.eu.net

http://x.org/package/X11rdf:Alt

ftp.x.org

ftp.cs.purdue.edu

ftp.eu.net

altid

rdf:type

rdf:_1

rdf:_2

rdf:_3

source


Statements About Statements (Requirement 2: Dispute

Statements)

• Making statements about statements requires a

process for transforming them into Resources

– subject the original resource

– predicate the original property

– object the original value

– type rdf:Statement


A Formal Model of RDF

• RDF itself is mathematically straightforward:

– Basic Definitions• Resources. • Properties Resources • Literals• Statements = Properties Resources {Resources

Literals}

– Typing• rdf:type Properties • {RDF:type, sub, obj} Statements obj Resources

– for triples like {p,r1,r2} the RDF spec should use some different bracketing, like (p,r1,r2)


Formal Model of RDF II

– Reification• rdf:Statement Resource-Properties• {rdf:predicate, rdf:subject, rdf:object } Properties• Reification of a triple {pred, sub, obj} of Statements is an

element r of Resources representing the reified triple and the elements s1, s2, s3, and s4 of Statements such that

– s1: {RDF:predicate, r, pred}– s2: {RDF:subject, r, sub} – s3: {RDF:object, r, obj} – s4: {RDF:type, r, [RDF:Statement]}

– Collections• { RDF:Seq, RDF:Bag, and RDF:Alt } Resources-Properties • There is a subset of Properties corresponding to the ordinals

(1, 2, 3, ...) called Ord. We refer to• elements of Ord as RDF:_1, RDF:_2, RDF:_3, ...


RDF Syntax I

• Data model does not enforce particular syntax• Specification suggests many different syntaxes

based on XML• General form:

<rdf:RDF> <rdf:Description about="http://www.w3.org/Home/Lassila"> <s:Creator>Ora Lassila</s:Creator> <s:createdWith rdf:resource=“http://www.w3c.org/amaya”/> </rdf:Description></rdf:RDF>

Starts an RDF-Description

Properties

Subject (OID)

Literal

Resource (possibly another RDF-description)


Resulting Graph

<rdf:RDF> <rdf:Description about="http://www.w3.org/Home/Lassila"> <s:Creator>Ora Lassila</s:Creator> <s:createdWith rdf:resource=“http://www.w3c.org/amaya”/> </rdf:Description></rdf:RDF>

http://www.w3c.org/amaya


Ora Lassila

s:createdWiths:Creator


RDF Syntax II: Syntactic Varieties

<s:Homepage rdf:about="http://www.w3.org/Home/Lassila” s:Creator=“Ora Lassila”/>

<s:createdWith> <s:HTMLEditor rdf:about=“http://www.w3c.org/amaya”/> </s:createdWith> </s:Homepage>

Typing InformationIn-Element Property

Property

Subject (OID)

http://www.w3c.org/amaya


Ora Lassila

s:createdWiths:Creator

HTMLEditor

s:Homepagerdf:type

rdf:type


RDF Schema (RDFS)

• RDF just defines the data model

• Need for definition of vocabularies for the data

model - an Ontology Language!

• RDF schemas are Web resources (and have

URIs) and can be described using RDF


Most Important Modeling Primitives

• Core Classes– Root-Class rdfs:Resource

– MetaClass rdfs:Class

– Literals rdfs:Literal

• rdfs:subclassOf-property

• Inherited from RDF: properties (slots)• rdfs:domain & rdfs:range• rdfs:label, rdfs:comment, etc.

• Inherited from RDF: InstanceOf (rdf:type)


RDF-Schema: Example

rdfs:Resource

xyz:MotorVehicle rdfs:Class

s s t

t

xyz:Truck

s

t

xyz:PassengerVehicle

s = rdfs:subClassOf t = rdf:type

xyz:Van s

s

xyz:MiniVan s

s

t t

t

t


Extensibility of RDF

• Define an Ontology of your Language with RDF

Schema (like RDF-Schema itself)

• Describe Instance Data using your new

Vocabulary

• Advantage: all Languages use the same Data

Model (simplifies Interoperability)


Protégé-2000 as RDF[S]-Editor

<rdfs:Class rdf:about="&mv;MotorVehicle"> <rdfs:subClassOf rdf:resource="&rdfs;Resource"/></rdfs:Class>

<rdfs:Class rdf:about="&mv;PassengerVehicle"> <rdfs:subClassOf rdf:resource="&mv;MotorVehicle"/></rdfs:Class>

<rdf:Property rdf:about="&mv;rearSeatLegRoom" a:maxCardinality="1" a:range="integer"> <rdfs:domain rdf:resource="&mv;MotorVehicle"/> <rdfs:range rdf:resource="&rdfs;Literal"/></rdf:Property>


Ontology Languages on Top of RDF:The Principle

Definition uses the data model of

Defined in terms of

RDF

RDF SchemaOntologyLanguage

Instance Data

Is extension of

Legend:


The Semantic Web

• A Web of machine understandable Data, based on declarative languages on top of RDF (all use the same data model!)• Intelligent Agent enabling architecture• W3C’s vision for the Semantic Web Architecture:

DARPA Agent Markup DARPA Agent Markup LanguageLanguage

DAMLDAML


DARPA Agent Markup Language Program

• DARPA funded Research Program (also funded the Development of the ARPANNET -> Internet)

• Focusing on building the foundation for the Semantic Web: http://www.daml.org

• Ontology Language DAML+OIL: Result of a Joint (European + US-American) Committee

• Rule Language in preparation


DAML+OIL

• Extension of RDF Schema• Ontology Language DAML+OIL: Result of a

Joint (European + US-American) Committee• Extension of RDF Schema

– Class Expressions (Intersection, Union, Complement)– XML Schema Datatypes– Enumerations– Property Restrictions

• Cardinality Constraints• Value Restrictions


Example: Intersection & Synonyms

<daml:Class rdf:ID="TallMan"> <daml:intersectionOf rdf:parseType="daml:collection">

<daml:Class rdf:about="#TallThing"/> <daml:Class rdf:about="#Man"/>

</daml:intersectionOf> </daml:Class>

<daml:Class rdf:ID="HumanBeing"><daml:sameClassAs rdf:resource="#Person"/>

</daml:Class>


Example: Disjoint & Complement<daml:Disjoint rdf:parseType="daml:collection"><daml:Class rdf:about="#Car"/> <daml:Class rdf:about="#Person"/> <daml:Class rdf:about="#Plant"/>

</daml:Disjoint>

<daml:Class rdf:ID="Car"><rdfs:comment>no car is a person</rdfs:comment> <rdfs:subClassOf>

<daml:Class><daml:complementOf rdf:resource="#Person"/>

</daml:Class> </rdfs:subClassOf>

</daml:Class>

Disjoint not strictly necessary, since expressible via pairwise subClassOfof complementOf, as for Car and Person:


Example: Properties (Transitive, Inverse, subProperty, UniqueProperty, range,

Datatypes)

<daml:TransitiveProperty rdf:ID="hasAncestor"/>

<daml:ObjectProperty rdf:ID="hasChild"><daml:inverseOf rdf:resource="#hasParent"/>

</daml:ObjectProperty>

<daml:UniqueProperty rdf:ID="hasMother"><rdfs:subPropertyOf rdf:resource="#hasParent"/><rdfs:range rdf:resource="#Female"/>

</daml:UniqueProperty>

<daml:DatatypeProperty rdf:ID="age"><rdf:type rdf:resource="http://www.daml.org/2001/03/daml+oil#UniqueProperty"/><rdfs:range rdf:resource="http://www.w3.org/.../XMLSchema#nonNegativeInteger"/>

</daml:DatatypeProperty>

Using User-defined Datatypes(based on XML Schema)

<xsd:simpleType name="over17">  <xsd:restriction base="xsd:decimal"> <xsd:minInclusive value="18"/> </xsd:restriction>

</xsd:simpleType>

<daml:Class rdf:ID="Adult"><daml:intersectionOf rdf:parseType="daml:collection">

<daml:Class rdf:about="#Person"/> <daml:Restriction><daml:onProperty rdf:resource="#age"/><daml:hasClass rdf:resource="somefile#over17"/>

</daml:Restriction> </daml:intersectionOf> </daml:Class>


Instances (Individuals)<Person rdf:ID="Adam">

<rdfs:label>Adam</rdfs:label> <rdfs:comment>Adam is a person.</rdfs:comment> <age><xsd:integer rdf:value="13"/></age> <shoesize>

<xsd:decimal rdf:value="9.5"/></shoesize>

</Person>

<daml:Class rdf:ID="Person"> . . .</daml:Class>


Protégé as OIL-Editor

• supports following subset of OIL:

– class definitions with subclass and slot constraints (property restrictions) with• class expressions: and, or, not, class[names], slot constraints, top, and bottom

• slot constraints: has-value, value-type, max-cardinality, min-cardinality, cardinality

• missing: concrete-type-exp, filler-exp

– slot definitions: • subslot-of, inverse (using Protégé's inverse slot mechanism), domain, range

• properties (transitive, symmetric, functional)

– global axioms (disjoint, covered, disjoint-covered, equivalent)

– missing: instance-of, related

• special widgets for displaying OIL expressions

• connects to FaCT description logic classifier for classification and satisfiability checking

• generates SHIQ LaTeX output

Application:Semantic Web Services

Source: Anupriya Ankolenkar, et al., “DAML-S: Semantic Markup For Web Services,”, Proceedings of SWWS’ 01, the First Semantic Web Working Symposium, California, USA, July 30 - August 1, 2001


Web Services

Serviceregistry

Servicerequester

Serviceprovider

FindWSDL, UDDI

PublishWSDL, UDDI

Bind

Servicedescriptions

Servicedescriptions

Services


What Is DAML-S

• Users and software agents should be able to discover, invoke, compose, and monitor Web resources offering particular services and having particular properties.

• As part of the DARPA Agent Markup Language program, we have begun to develop an ontology of services, called DAML-S.


Some Motivating Tasks

• Automatic Web service discovery• Automatic Web service invocation• Automatic Web service composition and

interoperation• Automatic Web service execution

monitoring


Top Level of the Service Ontology

Service

Resource

ServiceGrounding

ServiceProfile

ServiceModel

provide presents

supports

describedBy

(what it does)

(how it works)

(how to access it)


Process Modeling Ontology


Summary