Ontology from the perspective of MMF Ontology Registry OKABE, Masao ISO/IEC JTC1 SC32/WG2 MMF Ontology Registry UMTP (former CBOP) 4 November 2004

OKABE, Masao 2 About MMF Project MMF (Framework for Metamodel Interoperability) ISO/IEC19763 (project leader: Hajime Horiuchi, Jp) Part-1: Reference Model (Jp, UK) Part-2: MMF Core (Jp, Kr) Part-3: MMF Ontology Registry (Jp, Cn, Kr) Part-4: MMF Model Mapping (Jp)

4 November 2004OKABE, Masao 3 About MMF Ontology Registry Project A Joint project of experts from China, Korea and Japan Main Editor:Hajime Horiuchi Project members Japan;  Hajime Horiuchi (SC32-Jp, UMTP, Tokyo International Univ.)  Masao Okabe (SC32-Jp, UMTP, TEPCO)  Masaharu Obayashi (SC32-Jp, UMTP, K-three) China;  He Keqing (SC32-Cn, SKLSE, Wuhan Univ.)  He Yangfan (SC32-Cn, SKLSE, Wuhan Univ.)  Wang Chong (SC32-Cn, SKLSE, Wuhan Univ.) Korea;  Doo-Kwon Baik (SC32-Kr, Korea Univ.)  Sam Oh (SC32-Kr, Sungkyunkwan Univ.)

4 November 2004OKABE, Masao 4 Abstract MMF Ontology Registry links administration information to the ontology stored conforming to ODM. For that purpose, MMF Ontology Registry relies on DL metamodel of ODM. MMF Ontology Registry ODM

4 November 2004OKABE, Masao 5 Why is ontology? Objectives of ontology from the point of MMF Ontology Registry Mainly, to promote interoperability among various application systems. More generally, to provide common base to communicate and collaborate in some business domain or among deferent domains. Background Due to the proliferation of E-business and E-Commerce through the internet, there are a lot of application systems available on the internet. The number of available application systems is becoming larger and larger. The services provided by them evolve continuously. Note We think this view is within ODM and consistent with ODM

4 November 2004OKABE, Masao 6 What is ontology? We support the definition in ODM RFP ad/ ODM RFP ad/ says an ontology can range; Taxonomy  knowledge with minimal hierarchy or a parent/child structure Thesaurus  words and synonyms Conceptual Model  with more complex knowledge Logical Theory  with very rich, complex, consistent and meaningful knowledge

4 November 2004OKABE, Masao 7 What is ontology, compared with conceptual model? To actualize the our objectives of ontology, ontology has a feature, compared with conceptual model. That is, Continuous and autonomous evolution Ontologies have to evolve continuously and autonomously as each application system evolves continuously and autonomously.

4 November 2004OKABE, Masao 8 Difficulty caused by autonomous evolution This ontology has a definition of ‘green card’ and does not have a definition of ‘Christmas card’. This ontology does not have a definition of ‘green card’ but has a definition of ‘Christmas card’. Ontology for application system A Ontology for application system B Agent AAgent B Give me a ‘green card’. Green card??? I can give you a Christmas card. Christmas card??? To resolve this difficulty, source ontology is necessary.

4 November 2004OKABE, Masao 9 Source ontology and Local ontology Source Ontology3 Local Ontology for application system A Local Ontology for application system B Local ontology : localized ontology for some application system based on source ontologies relatively unstable and evolves autonomously and continually Source Ontology: standardized ontology for some business domain pre-defined and relatively stable Source Ontology1 Source Ontology2 ・ ・ ・

4 November 2004OKABE, Masao 10 Source Ontology and local ontology:Example Source Ontology + Green Card is … Source Ontology + Christmas card is … Source Ontology Local Ontology for application system A Local Ontology for application system B Card is … Certification is … Agent AAgent B Color is … Green is … Give me a green card. What is a green card? Is it a Christmas card whose color is green? No. A green card is a certification of working in the U.S. OK. I understand. Then, I cannot give you a green card. If agent A and B are human beings, this is easy task. But if agent A and agent B are computer agents, this is not so easy task.

4 November 2004OKABE, Masao 11 What is necessary for computer agents. For both source ontology and local ontology Machine-understandable formal description => ODM’s matter Administration information registration authority identification effective date etc. based on ISO/IEC MDR Part 3 =>MMF Ontology Registry's matter

4 November 2004OKABE, Masao 12 Scope of MMF Ontology Registry Scope of ODM

4 November 2004OKABE, Masao 13 Example one in ODM PRS 1 as source ontology (PersonlCar:Concept):Atomic_Onto_Construct administration information (Car:Concept):Atomic_Onto_Construct administration information (Vehicle:Concept):Atomic_Onto_Construct administration information (owns:Role):Atomic_Onto_Construct administration information (Person:Concept):Atomic_Onto_Construct administration information Example1:Source_Onto administration information MMF Ontology Registry ODM

4 November 2004OKABE, Masao 14 Other metaclasses with administration information in MMF Ontology Registry Onto_Domain Source_Onto Atomic_Onto_Construct Local_Onto SO_Component SOC_Variant Onto_Instances Onto_Concepts Onto_Selection

4 November 2004OKABE, Masao 15 Relation between ODM and MMF Ontology Registry ODM specifies ontology metamodel in several ontology descriptive languages MMF Ontology Registry links administration information to ontology stored conforming to ODM relies on DL metamodel of ODM because  DL metamodel is the core of ODM  two-way bounded mappings to/from DL and other ontology metamodels such as OWL, Topic Maps etc. shall be provided. Hence, we are very much interested in ODM, especially in DL metamodel and have several comments and questions.

4 November 2004OKABE, Masao 16 Why is DL the core of ODM? The main deference between DL and FOL is decidability, which DL usually has but FOL does not. Theoretically, decidability is very attractive. But, practically, it might not matter. Why does not ODM use FOL as its core, although FOL is still complete.

4 November 2004OKABE, Masao 17 Comment on DL metamodel in ODM PRS 1 * An expression is not necessarily in Tbox. For example, an expression “Female  Person(ANNA)” is in Abox. *: Ontology Definition Metamodel Preliminary Revised Submission to OMG RDP ad/ Volume1, 18 August 2004

4 November 2004OKABE, Masao 18 DL does not have variables DL does not have a quantification for a first argument of an atomic role. See next two slides in detail. Comment on Example 3 in ODM PRS 1 (1/3)

4 November 2004OKABE, Masao 19 Comment on Example 3 in ODM PRS 1 (2/3) Example 3 might be wrong in two points. As FOL, this is correct. The first point is that this uses x as a variable which is not introduced in DL. This situation sometimes happens because DL has only quantification for the second argument of Role. To resolve this situation, an inverse Role is necessary. Then, we have;  hasColor .Car  Color(red) So, this is an A-box expression for red:individual and cannot be a concept. That is, “ c1:Concept ” is not true. This is the second point.

4 November 2004OKABE, Masao 20 Comment on Example 3 in ODM PRS 1 (3/3) The diagram should be; red : Literal Color : DataType Car : Concept : Intersection : Existential : Inverse hasColor : Role e1 : Expression

4 November 2004OKABE, Masao 21 Example: MotherlessChild   hasChild .  Woman MotherlessChild:Concept e2:Expression e1:Expression e3:Expression e4:Expression hasChild:Role :Definition :Universal :Inverse :Negation Woman:Concept It is not easy for DL metamodel to specify that e3 must be an expression that can be defined as a role and that e4 must be an expression that can be defined as a concept. (see next example also) Does ODM intend to do this kind of things completely?

4 November 2004OKABE, Masao 22 Example: ParentWithDaughter   hasChild.  hasWife ParentWithDaughter:Concept e2:Expression e1:Expression e3:Expressione4:Expression hasChild:Role :Definition :Existential :Inverse:Negation hasWife:Role Obviously, this is a wrong example because hasWife is not a concept but a role. Does DL metamodel detect this kind of syntactical error completely?

4 November 2004OKABE, Masao 23 Example: Female  Child  Cat  Dog) e2:Expression e1:Expression:Intersection :Union Is this diagram correct? If yes, how can it is distinguished from (Female  Child)  Cat  Dog. If no, how does DL metamodel recognize the following two are same.  Female  Child  Cat  Dog))  (Female  Child)  Cat  Dog)) Female:Concept Child:Concept Cat:Concept Dog:Concept

4 November 2004OKABE, Masao 24 Question about two-way and bounded mapping on RFP Two-way According to the RFP  An instance of the ODM metamodel can be translated into an instance of some (e.g. OWL DL) metamodel and vice-versa. Unclear point  Since ‘can’ is not ‘must’, it is acceptable that some instances disappear through the mapping. Is it correct? Bounded According to the RFP  Repeated applications of the two-way mapping does not result in continually large user model. Unclear point  This means that through the mapping some information may lose but even finitely- many repeated applications may not result in nothing. Is it correct? If they are correct, MMF Ontology Registry faces a problem because it relies on DL metamodel even if ontology is described in other descriptive languages.

4 November 2004OKABE, Masao 25 Asking for permission To promote the co-operation of ODM and MMF Ontology Registry, it is a good idea to put ‘overview of ODM’ as an annex of MMF Ontology Registry standard. ‘Overview of ODM’ shall be a summary of RFP and Revised Submission Volume 1 and 2. We need the copyrighters(Gentleware, DSTC, IBM, Sandpiper )’ permission, because ‘Overview of ODM’ shall become open to all as an annex of MMF Ontology Registry 2 nd WD(or CD) some sentences and diagrams in the overview might be similar to the original ones.

4 November 2004OKABE, Masao 26 We are confident that the collaboration with ODM and MMF Ontology Registry will bring a fruitful outcome. Thank you.

4 November 2004OKABE, Masao 27  