1. Semantic Web Portal and Tools Ching-Long Yeh 葉慶隆 Department of Computer Science and Engineering Tatung University chingyeh@cse.ttu.edu.tw http://www.cse.ttu.edu.tw/chingyeh

2. Semantic Web Portal2 Outline A brief description to the Semantic Web Portal Architectural basis of the Semantic Web KA2: an ontology-based web portal An architecture of RDF triple data store Conclusions

3. Semantic Web Portal3 Introduction to Semantic Web Facilities to put machine-understandable data on the Web are becoming a high priority for many communities. The Web can reach its full potential only if it becomes a place where data can be shared and processed by automated tools as well as by people. For the Web to scale, tomorrow's programs must be able to share and process data even when these programs have been designed totally independently.

4. Semantic Web Portal4 Introduction to Semantic Web The Semantic Web is a vision: See “W3C Semantic Web Activity,” by Marja-Riitta Koivunen, for more descriptions.W3C Semantic Web Activity the idea of having data on the web defined and linked in a way that it can be used by machines not just for display purposes, but for automation, integration and reuse of data across various applications

5. Semantic Web Portal5 The Semantic Web Layered Architecture (http://www.w3.org/2001/T alks/0228-tbl/slide5-0.html) Tim Berners-Lee: “Axioms, Architecture and Aspirations” W3C all-working group plenary Meeting 28 February 2001 URIUnicode XMLNamespaces XML Schema Sig RDF M&S RDF Schema Ontology Rules Logic Proof Trust

6. The Big Picture of SW

7. Semantic Web Portal7 Web Portals A web portal is a web site that provides information content on a common topic. –General portals, e.g., Yahoo, Excite, Netscape, Lycos, CNET, MSN, and AOL.com –Specialized portal e.g., gardeners.com, semanticweb.org Making valuable information to be found –directory service, –search facility –news, e-mail, –community forum

8. Semantic Web Portal8 Ontology-Based Web Portals Ontology represents –common knowledge and interests sharing within their community Tasks that ontology can be used to support a portal –Accessing a portal Conceptual search and navigation Inference capabilities –Providing information Methods and tools accounting for the diversity of information sources

9. Semantic Web Portal9 Introduction to XML-Based Ontology URIUnicode XMLNamespaces XML Schema Sig RDF M&S RDF Schema Ontology Rules Logic Proof Trust

10. Semantic Web Portal10 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

11. Semantic Web Portal11 Namespace Bindings Prefixes are bound to namespace URIs by attaching an xmlns:prefix attribute to the prefixed element or one of its ancestors, prefix:name 1,..., prefix:name n 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:prefix 1,..., xmlns:prefix m

12. Semantic Web Portal12 XML Document Instance and DTD <mail:address xmlns:mail="http://www.deutschepost.de/" xmlns:tele="http://www.telekom.de/"> Xaver M. Linde Wikingerufer 7 10555 Berlin 12.50 030/1234567 030/1234568 030/1234569 76.20 <!ELEMENT address (name, street, town, bill, phone+, fax+, bill)>

13. Semantic Web Portal13 XML Schema An XML syntax that's an alternative and/or supplement to DTDs Data typing of element and attribute content

14. RDF M&S RDF (Resource Description Framework) –Beyond Machine readable to Machine understandable 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)

15. Semantic Web Portal15 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

16. Semantic Web Portal16 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/Lassila s:Creator Ora Lassila

17. Semantic Web Portal17 EmailName s:Creator http://www.w3.org/Home/Lassila Another Example To add properties to Creator, point through an intermediate Resource. Person://fi/654645635 Ora Lassila lassila@w3.org

18. Semantic Web Portal18 Example: Bag The students in course 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

19. Semantic Web Portal19 rdf:_1 rdf:_2 rdf:_3 rdf:type source ftp.eu.net ftp.cs.purdue.edu ftp.x.org Example: Alternative The source code for X11 may be found at ftp.x.org, ftp.cs.purdue.edu, or ftp.eu.net altid rdf:Alt http://x.org/package/X11

20. Semantic Web Portal20 RDF Syntax I Data model does not enforce particular syntax Specification suggests many different syntaxes based on XML General form: Ora Lassila Starts an RDF-Description Properties Subject (OID) Literal Resource (possibly another RDF-description)

21. Semantic Web Portal21 Resulting Graph Ora Lassila http://www.w3c.org/amaya http://www.w3.org/Home/Lassila Ora Lassila s:createdWith s:Creator

22. RDF Syntax II: Syntactic Varieties <s:Homepage rdf:about="http://www.w3.org/Home/Lassila” s:Creator=“Ora Lassila”/> Typing Information In-Element Property Property Subject (OID) http://www.w3c.org/amaya http://www.w3.org/Home/Lassila Ora Lassila s:createdWith s:Creator HTMLEditor s:Homepage rdf:type

23. Semantic Web Portal23 RDF Schema (RDFS) RDF just defines the data model Need for definition of vocabularies for the data model - an Ontology Language! The RDF Schema mechanism provides a basic type system for use in RDF models. The RDF schema specification language is less expressive, but much simpler to implement, than full predicate calculus languages such as CycL and KIF.

24. Semantic Web Portal24 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 )

25. Semantic Web Portal25 DAML+OIL: an Ontology Language 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

26. Semantic Web Portal26 Example: Intersection & Synonyms

27. Semantic Web Portal27 Example: Disjoint & Complement no car is a person Disjoint not strictly necessary, since expressible via pairwise subClassOf of complementOf, as for Car and Person :

28. Semantic Web Portal28 Example: Properties (Transitive, Inverse, subProperty, UniqueProperty, range, Datatypes)

29. Semantic Web Portal29 Using User-defined Datatypes (based on XML Schema) =18-->

30. Semantic Web Portal30 Instances (Individuals) Adam Adam is a person....

31. Semantic Web Portal31 Web Services

32. Semantic Web Portal32 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.

33. Semantic Web Portal33 Top Level of the Service Ontology Service Resource Service Grounding ServiceProfile ServiceModel provides presents supportsdescribed by (what it does) (how it works) (how to access it)

34. Semantic Web Portal34 Process Modeling Ontology

35. Semantic Web Portal35 Concept of ebXML Business Process Specification Schema

36. Semantic Web Portal36 Business Process Specification in XML

37. KA2 An Ontology-Based Community Web Portal

38. Semantic Web Portal38 KA2 Knowledge Annotation Initiative of the Knowledge Acquisition Community The basic scenario –WWW documents of the KS community were annotated according to the schema of an ontology. –The annotations enable intelligent access to these documents and infer implicit knowledge from explicitly stated facts and rules from the ontology.

39. The KA2 Ontology Class hierarchy Person Employee Academic-Staff Lecturer Researcher Administrative-Staff Secretary Technical-Staff Student Phd-Student Relations Address, Affiliation, Cooperates-With, Editor-Of,Email, First-Name, Has- Publication, Head-Of-Group, Head-Of- Project, Last-Name, Member-Of- Organization, Member-Of-Program- Committee, Member-Of-Research-Group, Middle-Initial, Organizer-Of-Chair-Of, Person-Name, Photo, Research-Interest, Secretary-Of, Studies-At, Supervises, Supervisor, Works-At-Project Person-ontology Class hierarchy On-Line-Publication Publication Article Article-In-Book Conference-Paper Journal-Article Technical-Report Workshop-Paper Book Journal IEEE-Expert IJHCS Special-Issue Relations Abstract, Book-Editor, Conference- Proceedings-Title, Contains-Article-In- Book, Contains-Article-In-Journal, Describes-Project, First-Page, Has- Author, Has-Publisher, In-Book, In- Conference, In-Journal, In-Organization, In-Workshop, Journal-Editor, Journal- Number, Journal-Publisher, Journal-Year, Last-Page, On-Line-Version, … Publication-ontology

40. Semantic Web Portal40 Accessing the Community Web Portal Query capability –In F-Logic mechanism Navigating capability –As the easy-to-use front-end of the query mechanism

41. Semantic Web Portal41 Query Capabilities For all publications of the researcher “Steffen Staab”. FORALL Pub <- EXISTS ResID ResID:Researcher[NAME->> Steffen "Staab"; PUBLICATION ->> Pub]. Two researchers cooperate, if a Researcher X works at a Project Proj and if a Researcher Y works at the same Project Proj and X is another person than Y FORALL X; Y; Proj X:Researcher[COOPERATESWITH ->> Y:Researcher] <- X:Researcher[WORKSATPROJECT->>Proj:Project] AND Y:Researcher[WORKSATPROJECT->>Proj:Project] AND NOT equal(X; Y ): Which researchers are cooperating with other r? FORALL ResID1, ResID2 <- ResID1:Researcher[COOPERATESWITH ->> ResID2].

42. Semantic Web Portal42 Navigating and Querying the Portal Query the portal using F-Logic is too inconvenient. Navigating and querying the web –A hypertext link may contain a query dynamically evaluated when clicking on the link (See P. 45) –Query generated by using the hyperbolic view interface (See P. 46) –Queries may be personalized and for the different users and available for the user in a selection list. –An expert mode: Querying the portal by typing an F-Logic statement

45. Semantic Web Portal45 Providing Information Integrating various syntactic and semantic formats based on the common ontology Three different modes of information provision are supported –Metadata-based information –Wrapper-based information –Fact-based information

46. Semantic Web Portal46 Metadata Metadata-based Information Information source Annotation tool In RDF, XML (OntoPad Annotea, …)

47. Semantic Web Portal47 Wrapper-based Information Annotating information sources by hand is time- consuming. Semi-structured Information sources (e.g., HTML) Structured Information sources (e.g., RDB) Wrapper program Metadata (Onto Wrapper)

48. Semantic Web Portal48 Fact-Based Information Fact Editor New facts create add, modify, delete Knowledge warehouse (Ontoedit, OilED, Protégé 2000)

49. Semantic Web Portal49 Development of Web Portals

50. Semantic Web Portal50 The System Architecture

51. Development of an Ontology-Based Portal for Digital Archive Services

52. Semantic Web Portal52 Introduction Goal

53. Semantic Web Portal53 Technical Architecture Content provision component Core component Service component

54. Semantic Web Portal54 Ontology Construction and Inference Engine In the portal, the semantic content and the control are separated. –The ontology and the knowledge warehouse are the schema and facts of the semantic content. –The inference engine controls the interpretation of rules specified in the service programs.

55. Semantic Web Portal55 Ontology Construction We first of all adapt for our purpose from the ontology developed in the KA2 project, building an ontology-based portal for the knowledge acquisition community. The KA2 ontology consists of –organization, –person, –publications, –projects, –events, –research topics and –products

56. Semantic Web Portal56 Ontology Construction To integrate the ontology with metadata from the content providers, we add metadata schema generally used in the field of digital libraries, DC and DC-Q, using the syntax of the ontology language DAML.

57. Semantic Web Portal57 Inference Engine flex –based on the logic programming system, Prolog, –supporting frame representation, forward and backward chaining inferences –local GUI, –connecting with web server, and –TCP/IP and agent libraries.

58. Semantic Web Portal58 Inference Engine To make use of flex, 1.Representing the ontology schema using the frame representation of flex; 2.Representing RDF instance as the flex instances; 3.Implementing each service program using backward and forward chaining rules

59. Semantic Web Portal59 RDFS in flex Frame frame ‘Journal’ is a ‘Publication’; default editor is a ‘Person’ and default publisher is an ‘Organization’ and default number is a ‘Number’ and default number is a ‘Number’.

60. Semantic Web Portal60 RDF Instances in flex 9.5 46 15 instance 'Peter' is a 'Person'; shoesize is 9.5 and age is 46 and shirtsize is 15.

61. Semantic Web Portal61

62. Semantic Web Tools

63. Semantic Web Portal63 Annotation " Annotation is necessary to add semantic content to your website." Annotation and authoring tools: http://annotation.semanticweb.org/tools

64. Semantic Web Portal64 Annotation and Authoring Tools Annotation and Authoring Tools OntoMat-Annotizer What is OntoMat-Annotizer ? –A user-friendly interactive webpage annotation tool –It supports the user with the task of creating and maintaining ontology-based DAML+OIL markups i.e. creating of DAML- instances, attributes and relationships.DAML –It includes an ontology browser for the exploration of the ontology and instances and a HTML browser that will display the annotated parts of the text.

65. OntoMat-Annotizer

66. Semantic Web Portal66 OntoMat-Annotizer 使用心得 此工具軟體對於要將網頁直接作標記和註記很 方便，允許你匯入設計好的資料格式，根據匯 入的 ontology 加入想要加註的內容。 此工具在中文碼的使用上有些問題，當我們將 網頁所需要的資訊做好標記之後，可以選擇將 這份檔案存成 HTML 文件，其內容將存於 HTML 的 中，但是中文的值在 存檔之後會變成亂碼。

67. Semantic Web Portal67 Other Annotation Authoring Tools OntoAnnotate: http://www.ontoprise.com/ The SHOE Knowledge Annotator: http://www.cs.umd.edu/projects/plus/SHOE/KnowledgeAnnotator.html Annotea Project http://www.w3.org/2001/Annotea/ Annozilla (Annotea on Mozilla) http://annozilla.mozdev.org/ COHSE Software http://cohse.semanticweb.org/software.html SMORE: Semantic Markup, Ontology and RDF Editor http://www.mindswap.org/~aditkal/editor.shtml etc.

68. Semantic Web Portal68 Ontology Editor Protégé Protégé allows domain experts to build knowledge- based systems by creating and modifying reusable ontologies and problem-solving methods. Protégé-2000 now has support for editing Resource Description Framework schema and instance data knowledge-bases.

70. Semantic Web Portal70 Protégé-2000 使用心得 這一套軟體對於 RDF(S) 的處理很方便，但是對於 daml+oil 的文件匯入有問題，若是單純想處理 RDF(S) 文件，這套 工具可以很容易的將概念和關聯性建立起來，根據這項概 念和關聯建立 Instance ，只要將數值對應的屬性中，就可 以產生 RDF 。 但是對於 daml+oil 的處理上會發生問題，所以如果想處理 daml+oil 的資料，我們建議使用 ontoedit 。

71. Semantic Web Portal71 Other Ontology Editing Tools OilEd http://oiled.man.ac.uk/ OntoEdit http://www.ontoprise.de/home

72. Semantic Web Portal72 Inference Engines for the Semantic Web Higher Order Logic Based Inference Engines Full First Order Logic Based Inference Engines Description Logic Datalog and Logic Programming Problem Solving Methods

73. Semantic Web Portal73 XSB and the Semantic Web XSB is a Logic Programming and Deductive Database system for Unix and Windows. Why is XSB interesting for the Semantic Web? –The Semantic Web need ways to specify declaratively how to process data on the Web. –XSB offers such a way: XSB is an efficient rule engine, freely available, open-source, and already used in a lot of different projects, which uses rules to process data. XSB Resources –http://xsb.sourceforge.net RDF Parsers

74. Semantic Web Portal74 RDF Parser

75. W3C Online RDF parser ：

77. Semantic Web Portal77 Ontology-Based Web Portal Ontology-Based Web Portal KAON Portal KAON PORTAL –A simple tool for generating multi-lingual, ontology- based Web portals. –KAON Portal is a simple tool for generating of ontology-based Web portals. –In order to create the portal, the user needs to create an ontology containing the information which will be presented in the Web.

78. Semantic Web Portal78 Ontology-Based Web Site Management OntoWebber OntoWebber is a Web site management system, which facilitates the creation, generation and maintenance of Web sites. Using OntoWebber, site engineers can build site models for domain-specific Web sites. The site models are based on explicit ontologies including the domain ontology and four distinct site- modeling ontologies.

79. Semantic Web Portal79 Conclusions We separate the semantic content the function control components to build a portal for digital library environment. With the separation, the portal can be divided into two parts, information provision and information access, working independently to each other. It also facilitates the development of services at the conceptual level, for example, the conceptual search and semantic navigation of the discovery activity. Furthermore, we are able to develop advanced services based on such knowledge base. The ontology and knowledge warehouse can be extended without changing the service programs.