Electronic Business: Concepts, Methodologies, Tools, and Applications (4-Volumes) P238 pptx

2304 Copyright © 2009, IGI Global, distributing in print or electronic forms without written permission of IGI Global is prohibited. Chapter 7.21 A Basis for the Semantic Web and E-Business: (IۋFLHQW2UJDQL]DWLRQRI2QWRORJ\ Languages and Ontologies Changqing Li National University of Singapore, Singapore Tok Wang Ling National University of Singapore, Singapore ABSTRACT This chapter introduces how to effectively orga- nize ontology languages and ontologies and how WRHI¿FLHQWO\SURFHVVVHPDQWLFLQIRUPDWLRQEDVHG on ontologies. In this chapter we propose the hierarchies to organize ontology languages and ontologies. Based on the hierarchy of ontology languages, the ontology designers need not bear in mind which ontology language the primitives exactly come from, also we can automatically DQGVHDPOHVVO\XVHWKHRQWRORJLHVGH¿QHGZLWK different ontology languages in an integrated en- vironment. Based on the hierarchy of ontologies, WKHFRQÀLFWVLQGLIIHUHQWRQWRORJLHVDUHUHVROYHG thus the semantics in different ontologies are clear without ambiguities. Also, these semantic- FOHDURQWRORJLHVFDQEHXVHGWRHI¿FLHQWO\SURFHVV the semantic information in Semantic Web and e-business. INTRODUCTION The Extensible Markup Language (XML) (Bray et al., 2004) developed by the World Wide Web Consortium (W3C) has recently emerged as a new standard for data representation and exchange on the Internet. However, the information exchange based on XML is at the syntactic level (Garshol & Moore, 2004). Nowadays, how to process and exchange semantic information becomes very important. Semantic Web and e-business are two important applications which need to process the 2305 A Basis for the Semantic Web and E-Business semantic information. Semantic Web (Lee, 1999) means that the Web pages are annotated with the concepts (terms and relationships) from sharing ontologies; because Web information refers to the sharing ontologies, computers can automatically understand and process the semantic information. Similarly, when different partners (agents) of e- business refer to the sharing concepts in ontolo- gies, they can semantically communicate with each other. This is a semantic e-business which is different from the traditional e-business. To process the semantic information, the traditional e-business is a person-to-person communication; now with ontologies the semantic communica- tion of e-business partners is an agent-to-agent communication. It can be seen that ontologies play a core role in processing semantic information. An ontology GH¿QHVWKHEDVLFWHUPVDQGUHODWLRQVKLSVFRPSULV- ing the vocabulary of a topic area, as well as the rules for combining terms and relationships to GH¿QHH[WHQVLRQVWRWKHYRFDEXODU\*UXEHU +RZ WR RUJDQL]H RQWRORJLHV DQG FOHDUO\ GH¿QH the semantics in ontologies are very important. Presently, the ontologies are built by different organizations for their own purposes, therefore we need to effectively organize different ontologies together with hierarchies, then the concepts of WKHRQWRORJLHVFDQEHHI¿FLHQWO\XVHGWRDQQRWDWH Web pages and e-business agents, and semantic LQIRUPDWLRQFDQ EHHI¿FLHQWO\SURFHVVHGEDVHG on the well-organized ontologies. 7R GH¿QH RQWRORJLHV ontology languages are required. Ontolingua (Gruber, 1992) is an ontology interchange language which was pro- posed to support the design of ontologies. Loom (MacGregor, 1991), a knowledge representation system, is used to provide deductive support. We will further introduce the XML-based ontology ODQJXDJHVLQWKH³%DFNJURXQG´VHFWLRQ I n t h i s c h a p t e r, w e p r o p o s e h i e r a r c h i e s t o e f f e c - tively organize ontology languages and ontologies DQGGLVFXVVKRZWRHI¿FLHQWO\SURFHVVVHPDQWLF information in Semantic Web and e-business. The rest of this chapter is organized as follows. ,QWKH³%DFNJURXQG´VHFWLRQZHLQWURGXFHWKH background and the motivation of this chapter. In WKH³2QWRORJ\/DQJXDJH2UJDQL]DWLRQ´VHFWLRQ the hierarchy to organize ontology languages is proposed. We propose the hierarchy to organize RQWRORJLHVDQGGLVFXVVKRZWRUHVROYHWKHFRQÀLFWV in the RQWRORJ\KLHUDUFK\LQWKH³%XLOGLQJ2QWRO- RJ\6\VWHP´VHFWLRQ+RZWRHI¿FLHQWO\SURFHVV the semantic information in the Semantic Web DQG HEXVLQHVV LV GLVFXVVHG LQ WKH ³6HPDQWLF Information Processing in the Semantic Web and (%XVLQHVV´VHFWLRQ,QWKH³&RQFOXVLRQ´VHFWLRQ we summarize this chapter. BACKGROUND Some comparisons have been done to compare different ontology languages. Although XML(S) has no semantics, it may help bootstrap the de- velopment of content and tools for the Semantic Web (Gil & Ratnakar, 2002). Another comparison (Gomez-Perez & Corcho, 2002) about ontology languages is from three aspects, that is, (1) general issues (partitions and documentation), (2) attri- butes (instance attributes, class attributes, local scope, and global scope), and (3) facets (default value, type constraints, cardinality constraints, and documentation). The existing works are mainly about comparing different ontology lan- guages, then choosing the best ontology language to use. Different from the existing works, this chapter is mainly about how to organize ontol- ogy languages and ontologies with hierarchies, therefore we mainly compare the changes of primitives in different ontology languages. From WKHVHFKDQJHVZHFDQ¿QGWKHFKDQJHWUHQGVRI ontology langu ages, t hen it is motivat ed, that is, it is very important to effectively organize different ontology languages. The Simple HTML Ontological Extensions 6+2(/XNH+HÀLQH[WHQGV+70/ with machine-readable knowledge annotated, 2306 A Basis for the Semantic Web and E-Business thus the implicit semantic information can be discovered by a computer. Although SHOE has the XML version, it is not based on the Resource Description Framework (RDF) (Lassila & Swick, 2004) and RDF Schema (RDFS) (Brickley & Guha, 2004). RDF (Lassila & Swick, 2004) is a standard ODQJXDJHRI:&IRUGH¿QLQJRQWRORJLHV5') GH¿QHVDVLPSOHPRGHOIRUGHVFULELQJUHODWLRQ- ships among resources in terms of properties and YDOXHV$UHVRXUFHUHSUHVHQWVDQ\WKLQJVSHFL¿HG Figure 1. The hierarchy of the RDF-based ontology languages Table 1. Some primitives of RDF and RDFS RDF RDFS DAML OIL DAML+OIL OWL Cat- egory Primitives Comment RDF rdf:ID Used to identify a class or property or any other resources rdf:resource Used to refer to a resource; a resource represents anything VSHFL¿HGE\D85, rdf:Property 7RGH¿QHDSURSHUW\WKH¿UVWOHWWHURIDSURSHUW\,'LVLQ lower case rdf:Bag An unordered collection (set) of members rdf:Seq An ordered collection (set) of members rdf:Alt A collection (set) of alternatives of members RDFS rdfs:Class 7RGH¿QHD&ODVVWKH¿UVWOHWWHURIDFODVV,'LVLQFDSLWDO rdfs:label To provide a human-readable version of a resource name rdfs:comment To provide a human-readable description rdfs:domain To restrict the domain of a property rdfs:range To restrict the range of a property rdfs:subClas- sOf To indicate the specialization of a class rdfs:subProper- tyOf To indicate the specialization of a property rdfs:Container Super class of rdf:Bag, rdf:Seq and rdf:Alt 2307 A Basis for the Semantic Web and E-Business E\ D XQLIRUP UHVRXUFH LGHQWL¿HU 85, /HH Fielding, & Masinter, 1998). Properties are the attributes of resources, which have either atomic entities (strings, numbers, etc.) or other resources as their values. For a person to understand the semantics of a sentence, a sentence is organized in a subject-verb-object (SVO) form. Similarly, the fundamental design pattern of RDF is to structure data as resource-property-resource triples. Here, resource can represent both subject and object in the SVO form, while property (relationship between resources) represents the verb in the 692IRUP7KXVWKH5')¿OHVFDQEHSURFHVVHG semantically. An RDF model can be represented in three ways, namely, graph syntax, triple syntax, and RDF/XML syntax. In this chapter, we focus on the XML representation of RDF. RDF organizes information in the SVO form, EXWLWGRHVQRWGH¿QHWKHPDQ\VWDQGDUGprimitives (see Table 1) required to construct ontologies. Thus, RDFS (Brickley & Guha, 2004) is created to provide some more basic primitives, such as ³VX E &OD V V 2I ´ D Q G³V XE3 U RS H U W \ 2 I ´ WR U H SUH V H QW  the relationships between classes or properties). More semantic-rich primitives are added into the successors of RDFS, namely, U.S. Defense Table 2. Primitive differences among DAML, OIL, DAML+OIL, and OWL OIL DAML DAML+OIL OWL Comment (1) Primitives included in all the four languages Class Class Class Class used to GH¿QHFODVV inverseRelation- Of inverseOf inverseOf inverseOf if P1(x,y) then P2(y,x) FunctionalProp- erty UniquePro- perty UniqueProperty Function- alProperty if P(x,y) and P(x,z) then y=z (2) Primitives not included in OIL, but included in the other three languages sameCl- assAs sameClassAs equiva- lentClass C1 = C2 sameProp- ertyAs samePropertyAs equiva- lentProperty P1 = P2 (3) New primitives added in DAML+OIL, used by OWL ObjectProperty Object- Property relates Resource to Resource DatatypeProp- erty Dataty- peProperty relates Re- source to Literal or data type (4) OIL primitives not used by DAML+OIL, but used by OWL SymmetricProp- erty Symmet- ricProperty if P(x, y), then P(y, x) 2308 A Basis for the Semantic Web and E-Business Advanced Research Projects (DARPA) DARPA Agent Markup Language (DAML) (Popp, 2000), Ontology Inference Layer (OIL) (Horrocks et al., 2001), DAML+OIL (Connolly et al., 2001a), and Web Ontology Language (OWL) (Harmelen et al., 2004). DAML (Popp, 2000), which is funded by DARPA aims at developing a language to fa- cilitate the semantic concepts and relationships understood by machines. The DAML language is based on RDF and RDFS. OIL (Horrocks et al., 2001), from the On-To- K n owle d ge P roj ec t , i s a n on t olog y r ep r es e nt a t ion language that extends RDF and RDFS with ad- ditional language primitives not yet presented in RDF and RDFS. Now the latest extension of DAML is DAML+OIL (Connolly et al., 2001b), which has some important features of OIL imported into DAML. Presently, DAML+OIL is evolving as OWL (Harmelen et al., 2004), and OWL is being promoted as the Web ontology language of W3C. OWL is almost same as DAML+OIL, but some primitives of DAML+OIL are renamed in OWL for more easily understanding. ,QWKH³+LHUDUFK\DQG3ULPLWLYHVRI5')DQG RDFS-Based Ontology Languages” section, we illustrate the hierarchies of the RDF-based ontol- ogy languages, and we compare the primitive differences among different ontology languages. Note that a primitive is a basic term in ontology ODQJXDJHVWKDWLVXVHGWRGH¿QHRQWRORJLHV,QWKH ³ 0R W LY D W LR Q´ V H FW L R QZHL Q W U R GXF H W KH P RW L YDW L RQ  of this chapter. Hierarchy and Primitives of RDF and RDFS-Based Ontology Languages RDF and RDFS are the ground of DAML, OIL, DAML+OIL, and OWL. In Table 1, we list some primitives of RDF and RDFS. 5')DQG5')6GH¿QHVRPHEDVLFSULPLWLYHV and these primitives are not capable of describing many other important concepts and relationships, for example, equivalentClass, therefore DAML, OIL, DAML+OIL, and OWL extend RDF and RDFS by adding some new primitives. In Table 2, we compare the primitive differences among DAML, OIL, DAML+OIL, and OWL. We sum- marize the differences into several cases, and for each case, we only list a few primitives which satisfy this case. Cases: (1) primitives included in all the four languages; (2) primitives not included in OIL, but included in the other three languages; (3) new primitives added in DAML+OIL, used by OWL; and (4) OIL primitives not used by DAML+OIL, but used by OWL. The four dif- ferent cases indicate the primitive relationships among different ontology languages. 1RZZHGLVFXVV KRZWRGH¿QHDQRQWRORJ\ based on ontology languages. Example 1. Consider a simple Person ontology VKRZQLQ)LJXUH7KHVWDUWWDJ³UGI5')!´DW OLQHDQGWKHHQGWDJ³UGI5')!´DWOLQH show that this ontology complies with the RDF syntax. Lines 1-4 specify some XML namespace declarations (Bray, Hollander, & Layman, 1999), WKHQZHFDQXVH³UGI´WRUHIHUWRWKHSULPLWLYHVGH- ¿QHGLQWKH85/³KWWSZZZZRUJ rdf-syntax-ns#” (similarly for other namespaces). 7KHQDPHVSDFH³[VG´DWOLQHLVXVHGWRUHIHU to XML Schema in which some data types are GH¿QHG/LQHVGH¿QHDFODVV³3HUVRQ´XVLQJ WKHSULPLWLYHRI2:/³RZO&ODVV´$OVRZHFDQ VHHIURPOLQHVDQGWKDWSULPLWLYHV³ODEHO´ DQG³FRPPHQW´DUHIURP5')6WKHUHIRUHWKHUH LVDQDPHVSDFH³UGIV´EHIRUH³ODEHO´DQG³FRP- PHQW´WKDWLV³UGIVODEHO´DQG³UGIVFRPPHQW´ /LQHV  GH¿QH D GDWD W\SH SURSHUW\ ³RZO 'DWDW\SH3URSHUW\´ ³RI¿FHBSKRQH´ VLPLODUO\ ZH FDQ GH¿QH RWKHU SURSHUWLHV IRU SHUVRQ IRU H[DPSOH³QDPH´DQGVRIRUWK/LQHVGH¿QH D SU R SH U W \ ³F R QW D F W B QX PEH U ´ ZK L FK LVH T X LY DO H QW  WRWKH³KRPHBSKRQH´ 5HPDUN7KH³3HUVRQ´DWOLQHLVDQRULJLQDO GH¿QLWLRQZKLOHWKH³3HUVRQ´DWOLQHKDVDKDVK PDUN³´EHIRUHZKLFKPHDQVWKH³3HUVRQ´DWOLQH 10 is a reference. There is no namespace (URL) 2309 A Basis for the Semantic Web and E-Business EHIRUH³3HUVRQ´DWOLQHEHFDXVH³3HUVRQ´LV GH¿QHGLQWKHVDPH¿OHDV³RI¿FHBSKRQH´%H- FDXVHWKH³VWULQJ´GDWDW\SHLVGH¿QHGLQ;0/ 6FKHPDQRWLQWKHVDPH¿OHDV³3HUVRQ´DQGWKH QDPHVSDFHRI;0/6FKHPDLV³[VG´WKHUHLVDQ ³[VG´EHIRUH³VWULQJ´DWOLQH 5HPDUN7KH¿UVWFKDUDFWHURIDFODVVQDPH LVLQXSSHUFDVHIRUH[DPSOHWKH³3´LQ³3HUVRQ´ LVLQXSSHUFDVH7KH¿UVWFKDUDFWHURIDSURSHUW\ QDPHLVLQORZHUFDVHIRUH[DPSOHWKH¿UVW³R´ LQ³RI¿FHBSKRQH´LVLQORZHUFDVH A conceptLVDWHUPGH¿QHGLQRQWRORJLHVZKLFK includes both the resources (entities) and the prop- HUWLHVUHODWLRQVKLSV)RUH[DPSOHWKH³3HUVRQ´ ³RI¿FHBSKRQH´DQG³FRQWDFWBQXPEHU´DIWHUWKH ³UGI,'´LQ)LJXUHDUHDOOFDOOHGFRQFHSWV Motivation Figure 1 shows the hierarchy of different ontology languages, and from Example 1, we know that the primitives of RDF, RDFS, and OWL are used WRJHWKHUWRGH¿QHDQRQWRORJ\2:/LVDUHSODFH- ment of DAML, OIL, and DAML+OIL, therefore the primitives of DAML, OIL, and DAML+OIL GR QRWDSSHDU LQ WKH GH¿QLWLRQ RI DQ RQWRORJ\ ZKLFK LV GH¿QHG ZLWK 2:/ +RZHYHU WKLV LV RQO\DQH[DPSOHZKLFKLVGH¿QHGQRZZLWKWKH OWL. In practice, before OWL appears, a lot of RQWRORJLHVKDYHDOUHDG\EHHQGH¿QHGZLWKRQWRO- ogy languages DAML, OIL, and DAML+OIL. &DQ ZH VWLOO XVH WKRVHRQWRORJLHV GH¿QHG ZLWK DAML, OIL, and DAML+OIL in the current OWL environment? The answer is yes, in this FKDSWHUZHFOHDUO\GH¿QHWKHKLHUDUFK\DQGWKH relationships among different ontology languages, and this hierarchy enables us to automatically use WKHSUHYLRXVRQWRORJLHVGH¿QHGZLWK'$0/2,/ and DAML+OIL. The second problem about the ontology lan- guage is that the primitives from different ontol- RJ\ODQJXDJHVVKRXOGEHXVHGWRJHWKHUWRGH¿QH the ontology. For example, from Example 1 and )LJXUHZHFDQVHHWKDW³UGI,'´³UGIVODEHO´ DQG³RZO&ODVV´DUHXVHGWRJHWKHUWRGH¿QHWKH c o n c e p t s i n o n t o l o g i e s . H o w e v e r , i t w i l l b e a b u r d e n Figure 2. A Person_Ontology represented using OWL language <rdf:R DF xmlns:rdf ="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns: rdfs=" http://www.w3.org/2000/01/rdf-schema#" xmlns:owl=" http://www. w3. org/2002/07/owl#" xmlns:xsd="http://www.w3.org/2000/10/X MLSchema#"> <owl:Class rdf:ID="Person"> <rdfs:label>Person</rdfs:label> </owl:Class> <owl:DatatypeProperty rdf:ID <rdfs: domain rdf:resource="#Person" /> <rdfs: range rdf: resource="xsd#stri ng"/> </owl: DatatypeProperty> <owl:DatatypeProperty rdf:ID="contact_number" > e" /> </owl: DatatypeProperty> … … </rdf:R DF> 2310 A Basis for the Semantic Web and E-Business for the ontology designer to bear in mind which ontology language the primitives are exactly from. Can we just use single namespace to refer to all the primitives, and the system can automatically translate the namespace to the proper namespaces, IRUH[DPSOHWKHRQWRORJ\GHVLJQHUFDQXVH³RZO´ as the namespace to refer to all the primitives, WKDWLV³RZO,'´³RZO,'´DQG³RZO&ODVV´DQG the system can automatically translate them back WR³UGI,'´³UGIVODEHO´DQG³RZO&ODVV´"7KH DQVZHULV\HV,QWKLVFKDSWHUZHFOHDUO\GH¿QH the relationships of the primitives in different o nt olog y l an g u a ge s, a nd t h is w i ll he lp to t r a n sla t e the single namespace to the proper namespaces. ,QWKLVZD\WKHHI¿FLHQF\RIWKHRQWRORJ\GHVLJQ can be improved. Moreover, the ontologies are presently de- signed by different organizations for their own purposes. If we can organize all of these ontologies in an integrated environment, we can improve the usability of ontologies, and the semantic informa- tion in the Semantic Web and e-business can be SURFHVVHGPRUHHI¿FLHQWO\ ONTOLOGY LANGUAGE ORGANIZATION In this chapter, we mainly focus on the theoretical analysis of organizing ontology languages and ontologies with hierarchies, so that this method can be widely used to organize different ontology languages and ontologies, though we implement a prototype tool to organize ontology languages DQGRQWRORJLHVLQWKH³$UFKLWHFWXUH´VHFWLRQ There already exist practical tools, for example, Daml2owl (Amin & Morbach, 2005), and so forth, that allow the translation from one language to another, but these tools are not general ones. They can only be used to translate between two V S HFL ¿ FR Q WROR J \ OD Q J X D J HV KRZHYH URX U P HW K R G  is a general one, which can be used to organize all the existing ontology languages as well as the future coming ontology languages. This is WKHPRVWLPSRUWDQWEHQH¿WRIRXUDSSURDFKRYHU prior works. ,QWKH³2SHUDWLRQVWR2UJDQL]H2QWRORJLHV´ VHFWLRQ ZH GH¿QH VRPH RSHUDWLRQV ZKLFK FDQ be used to describe the relationships among the primitives in different ontology languages. %DVHGRQWKHVHRSHUDWLRQVLQWKH³(DV\8VHRI Ontology Languages” section, we show how to DXWRPDWLFDOO\XVHWKHH[LVWLQJRQWRORJLHVGH¿QHG with DAML, OIL, and DAML+OIL and show how to automatically translate the namespace to the proper namespaces. Operations to Organize Ontologies We use the following operations to describe the relationships among the ontology languages and the primitives in ontology languages, that is, inheritance, block, atavism, and mutation. :HXVH³JPRH´DVWKHQDPHVSDFHEHIRUHHDFK RSHUDWLRQ³JPRH´UHSUHVHQWV³*HQHWLF0RGHOIRU Ontology (language) Engineering”, because these operations are borrowed from genetics. 1. Inheritance The inheritance relationships of ontology languages can be seen in Figure 1. RDFS inherits RDF; DAML and OIL inherit RDFS; DAML+OIL inherits both DAML and OIL; and OWL inherits DAML+OIL. The following example shows how WRXVHWKHLQKHULWDQFHRSHUDWLRQWRGH¿QHWKHUHOD- tionships between two ontology languages. Example 2. A s w e k n o w, DA M L + O I L i n h e r i t s both DAML and OIL. We use the inheritance operation shown in Figure 3 to indicate the inheri- tance relationship. With the inheritance operation, we need not copy the primitives in DAML and OIL into DAML+OIL. In DAML+OIL we only QHHGWRGH¿QHWKHQHZSULPLWLYHVZKLFKFDQQRW be inherited from DAML and OIL. 2311 A Basis for the Semantic Web and E-Business 2. Block It is not enough to indicate the relationships among ontology languages with the inheritance operation only. Some primitives in previous on- tology languages are not used by later ontology languages. We need to use the block operation to UHÀHFWWKLVUHODWLRQVKLS7KHIROORZLQJH[DPSOH shows how to use the block operation. Example 3. From Figure 1, we know that DAML+OIL inherits the primitives in both DAML D QG2,/EXWWKHSU L PLW LYH³6\ P PHWU LF3 URSHU W \´ of OIL is not used by DAML+OIL (see Table 2). We can use the block operation to indicate that this primitive is not used by DAML+OIL. 3. Atavism We found that some primitives blocked by the child ontology languages are reused by the descendant ontology languages. To process this kind of relationships we borrow the atavism mechanism in genetics. Atavism means that the characteristics of the grandparent do not appear at the child generation, but appear at the grandchild generation or the offspring of grandchild. We use an example to show how to use the atavism opera- tion to process the relationships of the primitives in ontology languages. Example 4.7KH³6\PPHWULF3URSHUW\´RI OIL is blocked by its child DAML+OIL, but the grandchild OWL again includes this primitive (see Table 2). Without our atavism operation, WKH GH¿QLWLRQ RI ³6\PPHWULF3URSHUW\´ RI 2,/ has to be copied into OWL, but with our atavism operation we only need to indicate in OWL that WKH³6\PPHWULF3URSHUW\´LQ2:/LVDQDWDYLVP RI WKH ³6\PPHWULF3URSHUW\´ LQ 2,/ ZKLFK LV shown in Figure 5. )LJXUH'H¿QLWLRQRI'$0/2,/EDVHGRQLQKHULWDQFHRSHUDWLRQ Figure 4. The use of block operation in DAML+OIL )LJXUH'H¿QLWLRQRI³6\PPHWULF3URSHUW\´LQ2:/EDVHGRQDWDYLVP <rdf:RDF xmlns:daml="http://www.daml.org/2000/10/daml-ont.daml#" xmlns:oil="http://www.ontoknowledge.org/oil/rdf-schema/2000/11/10-oil-standard#" gmoe:inheritance="daml, oil"> … … </rdf:R DF> <gmoe:block rdf:resource="oil#SymmetricProperty"/> <gmoe: atavism rdf:resource=" oil#SymmetricProperty"/> 2312 A Basis for the Semantic Web and E-Business  0XWDWLRQRURYHUULGHRUUHGH¿QH Furthermore, we use the mutation operation to describe the relationship that two primitives have the same name, but they have different semantics. See the following example. Example 5.5')6GH¿QHVSULPLWLYH³&ODVV´ DQG2:/DOVRGH¿QHVSULPLWLYH³&ODVV´7KRXJK WKHWZR³&ODVVHV´KDYHWKHVDPHQDPHWKH\KDYH GLIIHUHQWVHPDQWLFVWKH³&ODVV´LQ2:/SHUPLWV J UH DWH UH[SUH VVLYHQ HVV WK DQWKH ³&OD VV´L Q5 ')6  7KXVWKHSULPLWLYH³&ODVV´LQ2:/PXWDWHVWKH ³&ODVV´LQ5')6VHH)LJXUH Easy Use of Ontology Languages ,QWKH³2SHUDWLRQVWR2UJDQL]H2QWRORJLHV´ section, we discuss how to describe the relation- ships among the primitives in different ontology languages based on different operations. Based RQWKHUHODWLRQVKLSGHVFULSWLRQLQ³2SHUDWLRQVWR Organize Ontologies,” we can process the follow- LQJWZRSUREOHPVHI¿FLHQWO\DXWRPDWLFDOO\ XVHWKHH[LVWLQJRQWRORJLHVGH¿QHGZLWKRQWRORJ\ languages DAML, OIL, and DAML+OIL; and (2) automatically translate single namespace to proper namespaces.  8VLQJ RQWRORJLHV GH¿QHG ZLWK RQWRORJ\ languages DAML, OIL, and DAML+OIL Before OWL appeared many ontologies have EHHQGH¿QHG EDVHG RQ WKH RQWRORJ\ ODQJXDJHV DAML, OIL, and DAML+OIL. Now DAML, OIL, and DAML+OIL are being replaced by OWL, but if we can automatically translate all WKH RQWRORJLHV GH¿QHG ZLWK '$0/ 2,/ DQG '$0/2,/WRWKHRQWRORJLHVGH¿QHGZLWK2:/ we can save a lot of time in building new ontolo- gies based on OWL. Because we have described the relationships among different primitives in different ontology languages, we can automatically build a mapping between different primitives, thus the ontologies GH¿QHGZLWK'$0/2,/DQG'$0/2,/FDQ be automatically translated to the ontologies de- ¿QHGZLWK2:/:HXVHWKHIROORZLQJH[DPSOH for illustration. Example 6. Suppose that there is an ontology LQZKLFKDFRQFHSWLVGH¿QHGXVLQJWKHSULPLWLYH ³GDPOLQYHUVH2I´LQ'$0/%HFDXVH2:/in- herits DAML, and there are no changes for this primitive in DAML and OWL (see Table 2), we FDQGLUHFWO\WUDQVODWH³GDPOLQYHUVH2I´WR³RZO LQYHUVH2I´)XUWKHUPRUHLIDFRQFHSWLVGH¿QHG ZLWKWKHSULPLWLYH³RLO6\PPHWULF3URSHUW\´LQ 2,/ZHFDQWUDQVODWHLWWR³RZO6\PPHWULF3URS- HUW\´EHFDXVHWKH³6\PPHWULF3URSHUW\´LQ2:/ LV DQ DWDYLVP RI WKH ³6\PPHWULF3URSHUW\´ LQ OIL. There are no primitives in DAML, OIL, and DAML+OIL, which are blocked or overrided in OWL, therefore we need not consider these two RSHUDWLRQVLQWUDQVODWLQJWKHRQWRORJLHVGH¿QHG with DAML, OIL, and DAML+OIL to ontologies GH¿QHGZLWK2:/ With this technique, we can automatically XVHDOOWKHH[LVWLQJRQWRORJLHVZKLFKDUHGH¿QHG using the ontology languages DAML, OIL, and DAML+OIL. Therefore less effort will be paid to build new ontologies based on OWL. )LJXUH'H¿QLWLRQRI³&ODVV´LQ2:/EDVHGRQPXWDWLRQRSHUDWLRQ <gmoe: mutation rdf:resource="rdfs#Class"/> 2313 A Basis for the Semantic Web and E-Business 2. Using single namespace to refer to all primi- tives in different ontologies From Example 1 and Figure 2, we know that the primitives in RDF, RDFS, and OWL should EHXVHGWRJHWKHUWRGH¿QHDQRQWRORJ\,WZLOOEHD burden for the ontology designer to bear in mind where each primitive exactly comes from. Based on the organization of ontology languages in the ³2SHUDWLRQV WR 2UJDQL]H 2QWRORJLHV´ VHFWLRQ we can use single namespace to refer to all the SULPLWLYHVGH¿QHGLQGLIIHUHQWRQWRORJ\ODQJXDJHV and we can automatically translate the single namespace to the proper namespaces. Example 7.)RUWKHSULPLWLYHV³,'´³ODEHO´ DQG³&ODVV´WKHRQWRORJ\GHVLJQHUFDQXVHWKHP ZLWKWKHVDPHQDPHVSDFH³RZO´WKDWLV³RZO,'´ ³RZOODEHO´DQG³RZO&ODVV´$VZHNQRZIURP Figure 1, OWL inherits RDF and RDFS, thus we FDQVHDUFKWKH³,'´SULPLWLYHERWWRPXSWKDWLV VHDUFK2:/¿UVWO\WKHQ5')6DQGWKHQ5') 7KH³,'´SULPLWLYHLVIRXQGLQ5')WKHUHIRUHZH FKDQJHWKH³RZO,'´WR³UGI,'´6LPLODUO\WKH ³RZOODEHO´ZLOOEHWUDQVODWHGWR³UGIVODEHO´ZKHQ searching the ontology languages bottom up. For WKHSULPLWLYH³&ODVV´LWLVGH¿QHGLQERWK5')6 DQG2:/DQGWKH³&ODVV´LQ2:/LVDPXWDWLRQ RIWKH³&ODVV´LQ5')6:HZLOOXVHWKH³RZO &ODVV´UDWKHUWKDQWKH³UGIV&ODVV´EHFDXVHWKH ³&ODVV´LQ2:/LVDQPXWDWLRQDQGLWLVWKHODWHVW RQHDQGDFWXDOO\DOOWKHRQWRORJLHVDUHGH¿QHG ZLWK³RZO&ODVV´UDWKHUWKDQ³UGIV&ODVV´ The number of primitives in ontology lan- JXDJHVLVOLPLWHGDQGWKHLUUHODWLRQVKLSVDUH¿[HG therefore based on the organization and relation- ship descriptions of ontology languages in the ³2SHUDWLRQVWR2UJDQL]H2QWRORJLHV´VHFWLRQWKH WUDQVODWLRQVLQ³(DV\8VHRI2QWRORJ\/DQJXDJHV´ section can be done without ambiguities. BUILDING ONTOLOGY SYSTEM ,QWKH³2QWRORJ\/DQJXDJH2UJDQL]DWLRQ´VHFWLRQ we describe the hierarchy of different ontology languages based on the inheritance, block, ata- vism, and mutation operations. These operations can also be applied to the ontology building. As we know, the ontologies are now built by different organizations for their own purposes. It is important to organize these ontologies together in an integrated environment, then the semantic information in one domain is more complete. Only ZKHQWKHVHPDQWLFVLQRQHGRPDLQDUHDOOGH¿QHG clearly, it is true that the semantic information in Semantic Web and e-business can be processed correctly. ,QWKLVVHFWLRQZH¿UVWO\GLVFXVVKRZWRRUJD- nize ontologies based on the operations discussed LQ³2QWRORJ\/DQJXDJH2UJDQL]DWLRQ´$OVRZH summarize the guidelines for organizing ontolo- gies, that is, different information should be put at different hierarchies of ontologies. Furthermore, different from primitives in ontology languages, which will not change, the concepts in ontologies will change. When inserting or deleting a con- cept in ontologies, we should keep the ontologies consistent, otherwise it will hurt the ontologies to provide sharing information. Hence, we also GLVFXVVKRZWRUHVROYHWKHFRQÀLFWVLQRQWRORJ\ organizations. Architecture To make easy the use of inheritance, block, atavism, and mutation operations discussed in the ³2QWRORJ\/DQJXDJH2UJDQL]DWLRQ´VHFWLRQZH build a graphical tool to implement these opera- tions in ontology building. This tool can be applied to ontologies as well as ontology languages. Example 8. Figure 7 shows that, there exists a Person_Ontology, and we need to build a Stu- GHQWB2QWRORJ\7KHQLQWKH³3DUHQW2QWRORJLHV´ . chapter. Hierarchy and Primitives of RDF and RDFS-Based Ontology Languages RDF and RDFS are the ground of DAML, OIL, DAML+OIL, and OWL. In Table 1, we list some primitives of RDF and RDFS. 5')DQG5')6GH¿QHVRPHEDVLFSULPLWLYHV and. (partitions and documentation), (2) attri- butes (instance attributes, class attributes, local scope, and global scope), and (3) facets (default value, type constraints, cardinality constraints, and. print or electronic forms without written permission of IGI Global is prohibited. Chapter 7.21 A Basis for the Semantic Web and E -Business: (IۋFLHQW2UJDQL]DWLRQRI2QWRORJ Languages and Ontologies Changqing