We propose a tool to manage several sorts of relationships among RDF and RDFS. Our tool consists of three main functions: graphical editing of RDF contents, graphical editing of RDFS contents, and meta-model management facility. Metamodel management facility supports maintenance of relationship between RDF and RDFS contents. The above facilities are implemented based on plug-in system. We provide basic plug-in modules for consistency checking of RDFS classes and properties. The prototyping tool, called MR^3 (Meta-Model Management based on RDFs Revision Reflection), is implemented by Java language. Through the experiment of using MR^3, we show how MR^3 contributes the Semantic Web paradigm from the standpoint of RDFs contents management.

1. MR3: Meta-Model Management
based on RDFs Revision Reflection
Takeshi Morita1), Noriaki Izumi2),
Naoki Fukuta1), Takahira Yamaguchi3)
1) Shizuoka University, Japan
2) CARC, National Institute of AIST, Japan
3) Keio University, Japan

2. Contents
Motivation
Concept of Meta-Model Management
Implementations
Case Study
Conclusions

3. Contents
Motivation
Background
Issues
Our goal
Concept of Meta-Model Management
Implementations
Case Study
Conclusions

4. Background
(http://www.w3.org/2002/Talks/04-sweb/slide12-0.html)
The Semantic Web Stack
RDF, RDF Schema
an extension of the current web
in which information is given
well-defined meaning,
better enabling computers and people
to work in cooperation.
The Semantic Web

5. RDF (Resource Description Framework)
subject （Resource）
predicate （Property）
object （Resource）
hasFather
Statement
Model Personrdf:type
William
RDF: Framework for representing information on the Web
object （Resource）
Charles
Syntax (XML)
<rdf:Description about=“William”>
<hasFather rdf:resource=“Charles”/>
<rdf:type resource=“Person”/>
</rdf:Description>
Resource
Property
Resources are all things being described
by RDF expressions
A property is a relation between resources.

6. RDFS (RDF Vocabulary Description Language,
RDF Schema )
<rdf:Class rdf:about=“Person”>
<rdfs:subClassOf resource=“&rdfs;Resource”/> </rdf:Class>
<rdf:Property rdf:about=“hasFather”></rdf:Property>
Syntax (XML)
Model (The Same Model as a RDF Model)
hasFather rdf:Property
rdf:type
Person
rdfs:Classrdf:type
rdfs:Resource
rdfs:subClassOf
Class
Property
: Groups of related resources
: relationships between resources Meta-Model
RDFS
=
provides mechanisms for describing RDFS class and property

7. Issues
Because RDF is described by XML, it’s difficult
to build up RDF contents manually.
The main function of conventional tools is to display
XML based contents with RDF data model.
There still remains an issue as a difficulty of looking
the whole structure of both RDF and RDFS contents .

8. A Conventional Tool
RDFS
+
RDF
It’s difficult for a user to distinguish
RDF model from RDFS model .

9. Our Goal
<rdf:RDF xmlns:rdfs=“…rdf-syntax-ns”>
<image rdf:about="http://...">
<title>…</title></image>…
</rdf:RDF>
<rdf:RDF xmlns:rdfs=“…rdf-schema#">
<rdfs:Class rdf:about="http://purl.org/rss/1.0..."
<rdf:Property rdf:about="http://purl.org/rss/1.0..."
</rdf:RDF>
Class Property
Property
RDFS Document
RDF Document RDF Data Graph
RDFS Data Graph
(2)
(2) Graphical Editor of RDFS contents
(1) Graphical Editor of RDF contents
(1)
(3) Meta-Model Management Facilities
(3)
LiteralResource

10. Contents
Motivation
Concept of Meta-Model Management
Meta-Model Management
Meta-Model Management Facilities
Meta-Model Management Facilities examples
Implementations
Case Study
Conclusions

11. Meta-Model Management
authorPerson
RDFS Class RDFS Property
Meta-Model (RDFS)
author
Model (RDF)
Book
Book Person
The type of Resource
Resource Resource
RDF Property
rdfs:Resource rdf:Property
Crime and Punishment F.M. Dostoevsky
RDF (Model) and RDFS (Meta-Model) can be managed
separately and maintained their relationships automatically.

12. Meta-Model Management Facilities
Change RDFS Class and Property
Removal of RDFS Class and Property
Change the Type of RDF Resource and RDF
Property
Change the RDFS class name referred before the
user replace the type of an RDF resource
Make a new RDFS class which is not defined
The same is said of an RDF property
Import RDF File
etc
Modifying RDF and RDFS
Consistency checking of
classes and properties

13. Biblio
Biblio
Biblio
Book
Book
Meta-Model Management Facilities example （１）
Change RDFS Class
author
RDF
Person
author
RDFS
Book
rdfs:Resource
Person author
rdf:Property
Crime and Punishment
F.M. Dostoevsky
The Brothers Karamazov

14. Book
Book
Book
Biblio
Biblio
Meta-Model Management Facilities example （2）
Change the type of an RDF Resource
author
RDF
Person
author
RDFS
Biblio
rdfs:Resource
authorPerson
rdf:Property
Crime and Punishment
F.M. Dostoevsky
The Brothers Karamazov

15. Contents
Motivation
Approach
Concept of Meta-Model Management
Implementations
System Overview
Graphical Modeler of MR3
Movie
Case Study
Conclusions

16. User
RDF(S)
Document
s
RDF Parser
RDF Generator
Graphical
Modeler
Plug-in
Interface
RDF
RDFS
User Interface
MR3
Meta-Model
ManagementPlug-in
API
System Overview
MR3: Meta-Model Management
based on RDFs Revision Reflection
Input &Output
Main modules
Sub modules
Jena
JGraph

17. Graphical Modeler of MR3
Editor Windows Sub Windows
Class Editor Property Editor
RDF Editor
Attribute Dialog
Namespace Table

18. Movie
Three examples in Meta-Model Management Facilities
Change RDFS class
Change RDFS property
Change the type of an RDF Resource
Export RDF Model as XML Syntax

19. Contents
Motivation
Concept of Meta-Model Management
Implementations
Case Study
Discussion
Conclusions

20. Case Study
Purpose
To check that MR3 can separate and display RDF and
RDFS elements appropriately
Comparative Software
IsaViz
Popular tooｌ to build up RDF contents
World Wide Web Consortium offers
Visualize RDF and RDFS model similarly
Input Document
Creative Commons Schema and CC-GNU GPL (Mixed
RDF and RDFS)
Creative Commons is devoted to expanding the range of creative
work available for others to build upon and share.
http://creativecommons.org/
Creative Commons Schema is vocabularies to make metadata
about License
Software, Music, Movie, …
The CC-GNU GPL adds the Creative Commons' metadata and
Commons Deed to the Free Software Foundation's GNU General
Public License.
Commons Deed:
a human readable version of the license
<?xml version="1.0" encoding="SHIFT_JIS"?>
<rdf:RDF xmlns="http://web.resource.org/cc/"
xmlns:dc="http://purl.org/dc/elements/1.1/"
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
<Work rdf:about="">
<license rdf:resource="http://creativecommons.org/licenses/GPL/2.0/" />
<dc:type rdf:resource="http://purl.org/dc/dcmitype/Software" />
</Work>
<License rdf:about="http://creativecommons.org/licenses/GPL/2.0/">
<permits rdf:resource="http://web.resource.org/cc/Reproduction" />
<permits rdf:resource="http://web.resource.org/cc/Distribution" />
<requires rdf:resource="http://web.resource.org/cc/Notice" />
<permits rdf:resource="http://web.resource.org/cc/DerivativeWorks" />
<requires rdf:resource="http://web.resource.org/cc/ShareAlike" />
<requires rdf:resource="http://web.resource.org/cc/SourceCode" />
</License>
<rdfs:Class rdf:about="http://web.resource.org/cc/Agent">
<rdfs:subClassOf>
<rdfs:Class rdf:about="http://www.w3.org/2000/01/rdf-
schema#Resource"/>
</rdfs:subClassOf>
<dc:title>agent</dc:title>
<dc:description>
something (e.g. a person, corporation or computer) capable of creating
things<
/dc:description>
</rdfs:Class>
…..
Creative Commons' metadata (RDF/XML)
# Resources 30, # Literals 17, # Statements 64

21. Case Study: IsaViz
RDFS
+
RDF
It’s difficult for a user to understand
hierarchical relations of RDFS elements.
Class
hierarchy
Property
hierarchy ?

22. Case Study: MR3
RDFS
RDF
RDFS
Class
hierarchy
RDFS
Property
hierarchy
RDF
Data Graph
MR3 can separate and display
RDF and RDFS elements appropriately.

23. Discussion
A user can understand the graph of MR3
easier than IsaViz
RDF and RDFS elements are separated
Hide unnecessary elements for the user
Properties of RDFS model (such as “rdfs:domain”,
“rdfs:range”, “rdfs:comment”, …) and those values
rdf:type property and that value
The result of comparison between IsaViz and MR3

24. Contents
Motivation
Concept of Meta-Model Management
Implementations
Case Study
Conclusions

25. Conclusions
We have developed a meta-model management tool
for RDFs Contents
We have checked that MR3 can separate and
display RDF and RDFS elements appropriately
Future work
We’d like to make RDFs contents by MR3 and
check usefulness of meta-model management
facilities.