1. XML and Semantic Web 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. XML & SW2 Content Background XML, XML Protocol and Web Services Semantic Web: Machine Processable Web Ontology Basics XML-based Ontology Languages: RDFS, DAML, OWL DAML-S: an Ontology for Semantic Web Services Architecture for Managing the Metadata Layer of the Semantic Web Conclusions

3. XML & SW3 Background WWW –HTML –HTTP –Mainly man-machine interaction Electronic Business (EB) –Standard XML document –XML Protocol –AP-2-AP interaction Semantic Web Services –RDF –Ontology –Web Services, agents

4. XML & SW4 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

5. XML & SW5 XML Standards DTD Namespace Schema DOM CSS, XSL-T, XSL-FO XLink XPointer

6. XML & SW6 XML Protocol: SOAP

7. XML & SW7 <SOAP:Encelope xmlns:SOAP=http://schemas.xmlsoap.org/soap/envelope xmlns=“http://www.smallco.org/order” xmlns:xsi=http://www.w3.org/2001/XMLSchema-instance”> SterlingVommerce SmallCo Purchase Order bbc006751 Small Co Enterprise 123456789-0456 John Adams 214-340-1234 … … A SOAP Message

8. XML & SW8 Web Services

9. XML & SW9 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.

10. XML & SW10 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

11. XML & SW11 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

12. XML & SW12 The Big Picture of SW

13. Ontology Basics

14. XML & SW14 Why Develop an Ontology Reasons why developing an ontology: –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 –To analyze domain knowledge

15. XML & SW15 Ontologies One widely cited definition of an ontology is Gruber’s [Gruber 1993] “A specification of a conceptualization”.

16. XML & SW16 Ontologies Ontologies can be used to provide a concrete specification of term names and term meanings.

17. XML & SW17 What Is in an Ontology? For the purposes of tutorial an ontology is a formal explicit description of –concepts in a domain of discourse (classes (sometimes called concepts)), –properties of each concept describing various features and attributes of the concept (slots (sometimes called roles or properties)), and –restrictions on slots (facets (sometimes called role restrictions)). An ontology together with a set of individual instances of classes constitutes a knowledge base.

18. XML & SW18 A Simple Knowledge-Engineering Methodology There is no one “correct” way or methodology for developing ontologies. Here we discuss general issues to consider and offer one possible process for developing an ontology.

19. XML & SW19 A Simple Knowledge-Engineering Methodology Step 1: Determine the domain and scope of the ontology Step 2: Consider reusing existing ontologies Step 3: Enumerate important terms in the ontology Step 4: Define the classes and the class hierarchy Step 5: Define the properties of classes—slots Step 6: Define the facets of the slots Step 7: Create instances

20. XML & SW20 Uses Cases of Web Ontologies Web portal Multimedia collections Corporate web site management Design documentation Agents and services Ubiquitous computing

21. XML-Based Ontology Languages

22. XML & SW22 OWL Introduction OWL can be used to explicitly represent the meaning of terms in vocabularies and the relationships between those terms. –This representation of terms and their interrelationships is called an ontology. OWL has more facilities for expressing meaning and semantics than XML, RDF, and RDF-S, and thus OWL goes beyond these languages in its ability to represent machine interpretable content on the Web. OWL is a revision of the DAML+OIL web ontology language incorporating lessons learned from the design and application of DAML+OIL. From: http://www.w3.org/TR/2004/REC-owl-features-20040210/

23. XML & SW23 OWL Document Roadmap OWL is part of the growing stack of W3C recommendations related to the Semantic Web. –XML provides a surface syntax for structured documents, but imposes no semantic constraints on the meaning of these documents.XML –XML Schema is a language for restricting the structure of XML documents and also extends XML with datatypes.XML Schema –RDF is a data model for objects ("resources") and relations between them, provides a simple semantics for this data model, and these data models can be represented in an XML syntax.RDF –RDF Schema is a vocabulary for describing properties and classes of RDF resources, with a semantics for generalization-hierarchies of such properties and classes.RDF Schema –OWL adds more vocabulary for describing properties and classes: among others, relations between classes (e.g. disjointness), cardinality (e.g. "exactly one"), equality, richer typing of properties, characteristics of properties (e.g. symmetry), and enumerated classes. From: http://www.w3.org/TR/2004/REC-owl-features-20040210/

24. XML & SW24 OWL Why The OWL Use Cases and Requirements Document provides more details on ontologies, motivates the need for a Web Ontology Language in terms of six use cases, and formulates design goals, requirements and objectives for OWL.OWL Use Cases and Requirements Documentdetails on ontologiessix use cases design goalsrequirementsobjectives

25. XML & SW25 OWL Six Use Cases Web portal Multimedia collections Corporate web site management Design documentation Agents and services Ubiquitous computing

26. XML & SW26 OWL Design Goals Shared ontologies Ontology evolution Ontology interoperability Inconsistency detection Balance of expressivity and scalability Ease of use Compatibility with other standards Internationalization

27. XML & SW27 OWL Requirements R1. Ontologies as distinct resources R2. Unambiguous concept referencing with URIs R3. Explicit ontology extension R4. Commitment to ontologies R5. Ontology metadata R6. Versioning information R7. Class definition primitives R8. Property definition primitives R9. Data types R10. Class and property equivalence R11. Individual equivalence R12. Attaching information to statements R13. Classes as instances R14. Cardinality constraints R15. XML syntax R16. User-displayable labels R17. Supporting a character model R18. Supporting a uniqueness of Unicode strings

28. XML & SW28 OWL Objectives O1. Layering of language features O2. Default property values O3. Ability to state closed worlds O4. Range constraints on data types O5. Chained properties O6. Effective decision procedure O7. Commitment to portions of ontologies O8. View mechanism O9. Integration of digital signatures O10. Arithmetic primitives O11. String manipulation O12. Aggregation and grouping O13. Procedural attachment O14. Local unique names assumptions O15. Complex data types

29. XML & SW29 The Three Sublanguages of OWL OWL Lite a classification hierarchy and simple constraints OWL DL maximum expressiveness while retaining computational completeness OWL Full maximum expressiveness and the syntactic freedom of RDF with no computational guarantees

30. XML & SW30 OWL Lite Synopsis The list of OWL Lite language constructs RDF Schema Features: Class (Thing, Nothing) rdfs:subClassOf rdf:Property rdfs:subPropertyOf rdfs:domain rdfs:range Individual (In)Equality: equivalentClass equivalentProperty sameAs differentFrom AllDifferent distinctMembers Property Characteristics: ObjectProperty DatatypeProperty inverseOf TransitiveProperty SymmetricProperty FunctionalProperty InverseFunctionalProperty Property Restrictions: Restriction onProperty allValuesFrom someValuesFrom Restricted Cardinality: minCardinalityminCardinality (only 0 or 1) maxCardinalitymaxCardinality (only 0 or 1) cardinalitycardinality (only 0 or 1) Header Information: Ontology imports Class Intersection: intersectionOf Versioning: versionInfo priorVersion backwardCompatibleWith incompatibleWith DeprecatedClass DeprecatedProperty Annotation Properties: rdfs:label rdfs:comment rdfs:seeAlso rdfs:isDefinedBy AnnotationProperty OntologyProperty Datatypes xsd datatypes

31. XML & SW31 OWL DL and Full Synopsis The list of OWL DL and OWL Full language constructs that are in addition to or expand those of OWL Lite is given below. Class Axioms: oneOf, dataRange disjointWith equivalentClass equivalentClass (applied to class expressions) rdfs:subClassOf rdfs:subClassOf (applied to class expressions) Boolean Combinations of Class Expressions: unionOf complementOf intersectionOf Arbitrary Cardinality: minCardinality maxCardinality cardinality Filler Information: hasValue

32. XML & SW32 Language Description of OWL Lite OWL Lite RDF Schema Features Class: A class defines a group of individuals that belong together because they share some properties. Organized in a specialization hierarchy using subClassOf A built-in most general class named Thing –the class of all individuals and –a superclass of all OWL classes A built-in most specific class named Nothing –the class that has no instances and –a subclass of all OWL classes

33. XML & SW33 Language Description of OWL Lite OWL Lite RDF Schema Features rdfs:subClassOf: Class hierarchies may be created by making one or more statements that a class is a subclass of another class.rdfs:subClassOf wine vin......

34. XML & SW34 Language Description of OWL Lite OWL Lite RDF Schema Features rdf:Property: Properties can be used to state relationships between individuals or from individuals to data values. hasChild hasRelative hasSibling hasAge a person an integer occurrences of ObjectProperty occurrences of DatatypeProperty subclasses of the RDF class rdf:Property

35. XML & SW35 Language Description of OWL Lite OWL Lite RDF Schema Features rdfs:subPropertyOf : –Property hierarchies may be created by making one or more statements that a property is a subproperty of one or more other properties. –For example, hasSibling may be stated to be a subproperty of hasRelative. hasSibling hasRelative a person deduce......

36. XML & SW36 Language Description of OWL Lite OWL Lite RDF Schema Features rdfs:domain : A domain of a property limits the individuals to which the property can be applied. rdfs:range: The range of a property limits the individuals that the property may have as its value.

37. XML & SW37 Language Description of OWL Lite OWL Lite RDF Schema Features Individual : Individuals are instances of classes, and properties may be used to relate one individual to another.

38. XML & SW38 Language Description of OWL Lite OWL Lite Equality and Inequality equivalentClass : Two classes may be stated to be equivalent. The Wine class in the food ontology is precisely the same as the existing wine ontology. equivalentProperty : Two properties may be stated to be equivalent.

39. XML & SW39 Language Description of OWL Lite OWL Lite Equality and Inequality sameAs : Two individuals may be stated to be the same. differentFrom : An individual may be stated to be different from other individuals.

40. XML & SW40 Language Description of OWL Lite OWL Lite Equality and Inequality AllDifferent: A number of individuals may be stated to be mutually distinct in one AllDifferent statement. Note that owl:distinctMembers can only be used in combination with owl:AllDifferent

41. XML & SW41 Language Description of OWL Lite OWL Lite Property Characteristics inverseOf : One property may be stated to be the inverse of another property. If a property, P1, is tagged as the owl:inverseOf P2, then for all x and y : P1(x,y) iff P2(y,x)

42. XML & SW42 Language Description of OWL Lite OWL Lite Property Characteristics TransitiveProperty : Properties may be stated to be transitive. If a property, P, is specified as transitive then for any x, y, and z : P(x,y) and P(y,z) implies P(x,z) x= SantaCruzMountainsRegion y= CaliforniaRegion z= USRegion P= locatedIn xy P yz P and implies xz P

43. XML & SW43 Language Description of OWL Lite OWL Lite Property Characteristics SymmetricProperty : Properties may be stated to be symmetric. If a property, P, is tagged as symmetric then for any x and y : P(x,y) iff P(y,x) The MendocinoRegion is adjacent to the SonomaRegion and vice-versa. The MendocinoRegion is located in the CaliforniaRegion but not vice versa.

44. XML & SW44 Language Description of OWL Lite OWL Lite Property Characteristics FunctionalProperty : Properties may be stated to have a unique value. If a property, P, is tagged as functional then for all x, y, and z : P(x,y) and P(x,z) implies y = z

45. XML & SW45 Language Description of OWL Lite OWL Lite Property Characteristics InverseFunctionalProperty : Properties may be stated to be inverse functional. If a property, P, is tagged as InverseFunctional then for all x, y and z : P(y,x) and P(z,x) implies y = z

46. XML & SW46 Language Description of OWL Lite OWL Lite Property Restrictions allValuesFrom : The restriction allValuesFrom is stated on a property with respect to a class....... The maker of a Wine must be a Winery. The allValuesFrom restriction is on the hasMaker property of this Wine class only. Makers of Cheese are not constrained by this local restriction.

47. XML & SW47 Language Description of OWL Lite OWL Lite Property Restrictions someValuesFrom : The restriction someValuesFrom is stated on a property with respect to a class.... allValuesFrom For all wines, if they have makers, all the makers are wineries. someValuesFrom For all wines, they have at least one maker that is a winery.

48. XML & SW48 Language Description of OWL Lite OWL Lite Property Restrictions minCardinality, maxCardinality : Cardinality is stated on a property with respect to a particular class. –Cardinality expressions with values limited to 0 or 1 are part of OWL Lite. –This permits the user to indicate 'at least one', 'no more than one', and 'exactly one'. –Positive integer values other than 0 and 1 are permitted in OWL DL. –owl:maxCardinality can be used to specify an upper bound. owl:minCardinality can be used to specify a lower bound.

49. XML & SW49 Language Description of OWL Lite OWL Lite Property Restrictions cardinality : Cardinality is provided as a convenience when it is useful to state that a property on a class has both minCardinality 0 and maxCardinality 0 or both minCardinality 1 and maxCardinality 1. owl:cardinality, which permits the specification of exactly the number of elements in a relation. 1

50. XML & SW50 Language Description of OWL Lite OWL Lite Class Intersection intersectionOf : OWL Lite allows intersections of named classes and restrictions.

51. XML & SW51 Language Description of OWL Lite OWL Datatypes OWL uses most of the built-in XML Schema datatypes. The following datatypes are recommended for use with OWL: xsd:string xsd:normalizedString xsd:boolean xsd:decimal xsd:float xsd:double xsd:integer xsd:nonNegativeInteger xsd:positiveInteger xsd:nonPositiveInteger xsd:negativeInteger xsd:long xsd:int xsd:short xsd:byte xsd:unsignedLong xsd:unsignedInt xsd:unsignedShort xsd:unsignedByte xsd:hexBinary xsd:base64Binary xsd:dateTime xsd:time xsd:date xsd:gYearMonth xsd:gYear xsd:gMonthDay xsd:gDay xsd:gMonth xsd:anyURI xsd:token xsd:language xsd:NMTOKEN xsd:Name xsd:NCName

52. XML & SW52 Language Description of OWL Lite OWL Lite Header Information OWL Lite supports notions of ontology inclusion and relationships and attaching information to ontologies. v 1.17 2003/02/26 12:56:51 mdean An example ontology

53. XML & SW53 Language Description of OWL Lite OWL Lite Annotation Properties and Versioning OWL Lite allows annotations on classes, properties, individuals and ontology headers. RDF already has a small vocabulary for describing versioning information. OWL significantly extends this vocabulary.

54. XML & SW54 Incremental Language Description of OWL DL and OWL Full Both OWL DL and OWL Full use the same vocabulary although OWL DL is subject to some restrictions. Roughly, OWL DL requires type separation (a class can not also be an individual or property, a property can not also be an individual or class). This implies that restrictions cannot be applied to the language elements of OWL itself (something that is allowed in OWL Full). Furthermore, OWL DL requires that properties are either ObjectProperties or DatatypeProperties The OWL Semantics and Abstract Syntax document explains the distinctions and limitations. We describe the OWL DL and OWL Full vocabulary that extends the constructions of OWL Lite below.

55. XML & SW55 Incremental Language Description of OWL DL and OWL Full oneOf: (enumerated classes): Classes can be described by enumeration of the individuals that make up the class.

56. XML & SW56 Incremental Language Description of OWL DL and OWL Full hasValue : (property values): A property can be required to have a certain individual as a value (also sometimes referred to as property values)....

57. XML & SW57 Incremental Language Description of OWL DL and OWL Full disjointWith : Classes may be stated to be disjoint from each other.

58. XML & SW58 Incremental Language Description of OWL DL and OWL Full unionOf, complementOf, intersectionOf (Boolean combinations): OWL DL and OWL Full allow arbitrary Boolean combinations of classes and restrictions: unionOf, complementOf, and intersectionOf.

59. XML & SW59 Incremental Language Description of OWL DL and OWL Full minCardinality, maxCardinality, cardinality (full cardinality): While in OWL Lite, cardinalities are restricted to at least, at most or exactly 1 or 0, full OWL allows cardinality statements for arbitrary non- negative integers. 1

60. XML & SW60 Incremental Language Description of OWL DL and OWL Full complex classes : –In many constructs, OWL Lite restricts the syntax to single class names (e.g. in subClassOf or equivalentClass statements). –OWL Full extends this restriction to allow arbitrarily complex class descriptions, consisting of enumerated classes, property restrictions, and Boolean combinations. –Also, OWL Full allows classes to be used as instances (and OWL DL and OWL Lite do not).

61. XML & SW61 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)

62. XML & SW62 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

63. XML & SW63 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

64. XML & SW64 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

65. XML & SW65 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

66. XML & SW66 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

67. XML & SW67 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)

68. XML & SW68 Resulting Graph Ora Lassila http://www.w3c.org/amaya http://www.w3.org/Home/Lassila Ora Lassila s:createdWith s:Creator

69. XML & SW69 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

70. XML & SW70 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.

71. XML & SW71 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 )

72. XML & SW72 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

73. OWL-S: An Ontology for Semantic web Service

74. XML & SW74 Motivation Tasks of 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.

75. XML & SW75 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)

76. XML & SW76 Process Modeling Ontology

77. Applications of Ontology

78. XML & SW78 Ontology library sites http://protege.stanford.edu/plugins/owl/ontologies.html http://www.daml.org/ontologies/keyword.html http://www.mindswap.org/2003/owl/

79. XML & SW79 Ontology

80. XML & SW80 travel

81. XML & SW81 travel

82. XML & SW82 wine

83. XML & SW83 wine

84. XML & SW84 travel

85. XML & SW85 travel

86. XML & SW86 travel

87. XML & SW87 wine

88. XML & SW88 wine

89. Protégé 使用說明

90. XML & SW90 編輯新檔

91. XML & SW91 選擇 OWL Files

92. XML & SW92

93. XML & SW93 增加 class

94. XML & SW94 更名所要的 class name

95. XML & SW95 編輯完的 Class 跟 slot 的增加

96. XML & SW96 儲存檔案選擇 namespace

97. XML & SW97 增加 plugin

98. XML & SW98 Query

99. XML & SW99 Protégé 輸出 HTML

100. XML & SW100

101. Semantic Web Applications

102. XML & SW102 An Architecture of Semantic Community Web Portals (From: http://www9.org/w9cdrom/134/134.html)

103. XML & SW103 A KM Framework over SW (From: http://www2002.org/CDROM/poster/130.pdf)

104. XML & SW104