Full paper presentation at EKAW2010.

1. EKAW2010 12th Oct. 2010, Lisbon, Portugal Practical Considerations on Identity for Instance Management in Ontological Investigation KoujiKozaki, Satoshi Endo, and RiichiroMizoguchi The Institute of Scientific and Industrial Research, Osaka University, Japan 2010/10/12 1 EKAW2010

2. Agenda of My Talk Motivation Identity of normal type(concepts which are not roles) Kinds of identity in general Consideration on instance identity 4 kinds of instance identities Identity for Exactness (Numerical identity) Identity for Essentiality Identity for Counting Identity for Replacement Identity of roles Model of roles Identities of constituent role and post role Concluding remarks 2010/10/12 2 EKAW2010

3. Motivation The identity discussed in philosophy(numerical identity) Any P, P(X) = P(Y)  X and Y are identical Not very practical for talking about identities of individuals! Instance identity of normal types (1) Replacing parts of your bike Instance identity of roles (2) Counting the number of guests of a restaurant The total number of guests in a month Special menu for frequent customer (3) The number of parliament members When a member resigns, a vacancy appears. There is no difference between all 480 vacancies. It's Notmy bike anymore! I’m fixing this bike. I’m fixing this bike. … 2010/10/12 EKAW2010 What bike aye you fixing ? We investigate the kinds of identities and their characteristics from practical point of view. 480 Japanese lower house 3

4. Kinds of Identity Class identity of a thing Identity for discussing the sameness of the class individuals belong to. Instance identity Identity for discussing the sameness of instances as they are. Synchronic identity represents the fact that two individuals are the same thing at a given time. Diachronic identity discusses the sameness of instances at two time points. 2010/10/12 4 Essential property A property which determines the identity of its instances. Same or Not Not your Porsche any more! Porsche it changes its instance identity Beetle It keeps its class identity EKAW2010 Different in terms of class identity This talk Class identity vs. Instance identity replace

5. We consider kinds of identity according to their strength. 2010/10/12 5 Consideration of Instance Identity How strictly the sameness of instances is judged (2) They are the same because the change is negligible. (1)Strictly speaking, they are different. > a bolt of an instance of bike is replaced with another one Before After just counting the number of guest < counting who came how many times We discuss four kinds of identities according to their strength and features. EKAW2010

6. Identity for Exactness(Iex) Identity which means the exact sameness. It corresponds to numerical identity. How rigidly Iex discusses the exact sameness? Every instance of a physical entity changes as time goes by. e.g. A bike rusts as time goes by and changes in terms of Iex. e.g. An instance of person “John” at present and him five minutes ago are different in terms of Iexat the two time points. Different in terms of Iex Different in terms of Iex Replacement of a bolt 5 min. ago present They are often recognized as the same in practice ->It is necessary to define identities which are weaker than Iex . 2010/10/12 6 EKAW2010 It rusts as time goes by

7. Identity for Essentiality (Ies) Identity which is defined by essential property. e.g. essential property of John's bike is a comfortable saddle which he has used for ten years. The bike keeps Ies1unless the saddle has been changed. When the saddle (its essential property) is replaced with another, the Ies1 changes . Essential to John Ies1 Ies1 Ies2 Changed! t1 t2 t3 The same in termsof Ies Different in terms of Ies Notice: From an engineering viewpoint, we permit arbitrariness to capture an essential property of a concept. 2010/10/12 7 EKAW2010

8. Identity for Counting (Ico) Task of counting the number of instances We do not consider the details of each instance discussed in terms of Iex or Ies if following three conditions are satisfied: (1) we can recognize whether instances are the target to count or not. (2) we can distinguish each from others. (3) we can avoid duplicate counting. Identity for Counting (Ico)[synchronic identity] : Identity which argues about the number of instances satisfying the above three conditions. e.g. There are five bikes in terms of Icobike 1~5. Icomotorbike1 Icobike1 Icobike2 Icobike3 Icobike4 Icobike5 Icomountain bike 1 Icomountain bike 2 2010/10/12 8 EKAW2010

9. 2010/10/12 9 EKAW2010 A Counting as a Real-world Task We need non-zero time to accomplish counting. If some parts of the target instance of counting are replaced during the counting task, we would fail to count them. e.g. three bikes (A~C) , their essential properties are two wheels. Ico can’t be used for discussing whether the bike changes its identity or not after its part replacement because it is synchronic identity. Different in terms of Ies The number of bikes is 4 ! A ? Ies1 Ies1 Ies 4 Ies 4 Ies1 Ies1 Ies 4 Ies 4 ✓ A’ ✓ ? ? ? Ies2 Ies2 Ies2 Ies2 Ies2 Ies2 Ies2 Ies2 Ies2 Ies2 Ies2 Ies2 B B B (✓) ✓ : being counted (✓):has been counted ✓ Ies3 Ies3 Ies3 Ies3 Ies3 Ies3 Ies3 Ies3 Ies3 Ies3 Ies3 Ies3 C C C ✓ t1 t2 t3 We need another identity weaker than Ies.

10. 2010/10/12 10 EKAW2010 Identity for Replacement(Ire) Identity which an instance of the whole continues to be itself without becoming another thing while whose parts are being replaced independently of their kinds and number of the replaced parts. Different in terms of Ies The same in terms of Ire A’ ✓ (✓) Ire1 Ire1 Ire1 A ? Ies1 Ies1 Ies 4 Ies 4 A Ies1 Ies1 Ies 4 Ies 4 (✓) ✓ : being counted (✓):has been counted ✓ Ire2 Ire2 Ire2 ? ? ? Ies2 Ies2 Ies2 Ies2 Ies2 Ies2 Ies2 Ies2 Ies2 Ies2 Ies2 Ies2 B B B B ✓ Ire3 Ire3 Ire3 Ies3 Ies3 Ies3 Ies3 Ies3 Ies3 Ies3 Ies3 Ies3 Ies3 Ies3 Ies3 C C C C t1 t2 t3 We can count the number of three bikes correctly.

11. Agenda of My Talk Motivation Identity of normal type(concepts which are not roles) Kinds of identity in general Consideration on instance identity 4 kinds of instance identities Identity for Exactness (Numerical identity) Identity for Essentiality Identity for Counting Identity for Replacement Identity of roles Model of roles Identities of constituent role and post role Concluding remarks 2010/10/12 11 EKAW2010

12. Fundamental Scheme of Our Role Model “In a context, there are players who play role concepts and thereby become role holders”. “In a restaurant, there are persons who play guestrolesand thereby become guests.” Role-Holder Guest Context Role Concept Player Restaurant GuestRole Person Identity of role-holder is composed by the role concept and the player Class playable depend on Role-Holder Role-Holder Guest-1 Instance Guest-1 Guest-1 vacant role Restaurant A GuestRole-1 John GuestRole-1 John John playing Context depend on Role-playing thing Role Concept 2010/10/12 12 EKAW2010 playing Role-playing thing “In Restaurant A, John plays guest role-1 and thereby becomes guest-1”

14. constituent role represents the player’s participation in the context to become a constituent of the context.

15. post role represents what kinds of post the player is required to fulfill. Guest role at class level Role-Holder Guest Context Role Concept Potential Player Restaurant GuestRole Person Identity of role-holders are determined by role concepts and its players playable depend on Guest role at class level Role-holder Context Guest Guest Restaurant Potential player Role-holder Restaurant Constituent depend on Restaurant Constituent Restaurant Constituent Role-holder Constituent Role Post Role Potential player Guest Post Role Guest Post Role depend on Restaurant Constituent Role Restaurant Constituent Role Person Person playable playable EKAW2010 Played by constituent role holder

16. Example: Guests of a Restaurant in the Instance Level Role-holder Context Guest Restaurant Potential player Role-holder Restaurant Constituent Constituent Role Post Role Potential player Guest Post Role Restaurant Constituent Role Person playable Class Instance playable Context Role-holder Guest-1 Restaurant A Role-holder Restaurant A Constituent-1 Role-holder Restaurant A Constituent Role-1 Guest-2 John Guest Post Role of Restaurant A playing Role-holder Role-playing thing Instance of Constituent Role Restaurant A Constituent-2 Instance of Post Role Instances of constituent role (in the case of guests of a restaurant) -created at the same time of new players’ participation. -disappears when the player stops the participation. Specification of what a player is expected to play. (only one post role for each role concept in the context) Role-playing thing playing Restaurant A Constituent Role-2 Mary Legends The Guest Post Role is sharedbymultiple constituent roles playing depend on playable/playing Role-playing thing playing Instance of Constituent Role instance-of Role-playing thing relationship between role-holder and individual role-holder 2010/10/12 14 EKAW2010

17. Discussion: Counting the Number of Guests (1/3) 文章減らす方向 で調整 Role-holder Context Guest Restaurant Potential player Role-holder Restaurant Constituent Constituent Role Post Role Potential player Guest Post Role Restaurant Constituent Role Person When we count the number of guests of a restaurant in a month. playable Class Instance playable Context Role-holder Guest-1 Restaurant A Role-holder If we need to know in what order each guest comes Restaurant A Constituent-1 Restaurant A Constituent-1 Ies-1 Role-holder Restaurant A Constituent Role-1 Guest-2 John Guest Post Role of Restaurant A playing Role-holder Role-playing thing Instance of Constituent Role Ico-1 Restaurant A Constituent-2 Instance of Post Role Role-playing thing playing If we want to count only total number of guests Restaurant A Constituent Role-2 Mary Legends playing depend on playable/playing Role-playing thing playing Instance of Constituent Role instance-of Role-playing thing relationship between role-holder and individual role-holder 2010/10/12 15 EKAW2010

18. Discussion:Counting the number of Guests(2/3) Services for Guests Role-holder Context Guest Restaurant Potential player Frequent customer Post Role When you want to serve special menu to frequent customer. Role-holder Restaurant Constituent Constituent Role Post Role Potential player SubClassOf Guest Post Role Restaurant Constituent Role Person playable Class Instance playable Context Role-holder Guest-1 Restaurant A Role-holder Frequent customer Post Role of Restaurant A Restaurant A Constituent-1 Role-holder Ies Restaurant A Constituent Role-1 Guest-2 John Guest Post Role of Restaurant A Guest Post Role of Restaurant A playing Role-holder Role-playing thing Instance of Constituent Role Restaurant A Constituent-2 All guests are served the same service at the restaurant. Instance of Post Role Role-playing thing playing Restaurant A Constituent Role-2 we need to know how many times each person comes and plays the guest post role, using Ies of person. Mary Legends playing depend on playable/playing Role-playing thing playing Instance of Constituent Role instance-of Role-playing thing relationship between role-holder and individual role-holder 2010/10/12 16 EKAW2010

19. When the same person visits to the restaurant twice. 2010/10/12 17 Discussion:Counting the number of Guests (3/3) The Guest who Visits Twice First time Role-holder Context Guest-1 Restaurant A Role-holder Restaurant A Constituent-1 Restaurant A Constituent Role-1 John Not identical in terms of Ies Guest Post Role of Restaurant A playing Role-playing thing Instance of Constituent Role Instance of Post Role Role-playing thing playing The same in terms of Ies The same in terms of Ies Different in terms of Ies Second time Guest-2 Role-holder Restaurant A Constituent-2 Guest Post Role of Restaurant A Restaurant A Constituent Role-2 John It is properly managed in what mean guest role-holders are the same or different using these five kinds of instances and their identities. playing Role-playing thing Instance of Constituent Role Instance of Post Role playing Role-playing thing EKAW2010

20. Discussion:Parliament members(1/3) Japanese lower house 2010/10/12 18 Role-holder Context Parliament Member of J. Lower House-xx Japanese Lower House Role-holder Parliament Member Constituent-xx Parliament Member Constituent Role-xx Person-abc playing Instance of Post Role Role-playing thing Instance of Constituent Role J. Lower House Post Role playing Role-playing thing . . . . . . only one instance of parliament post role exists 480 Role-holder Parliament Member of J. Lower House-zz playing Role-holder Parliament Member Constituent-zz Parliament Member Constituent Role-zz Person-xyz playing Role-playing thing Instance of Constituent Role Role-playing thing EKAW2010

21. Discussion:Parliament members(2/3) Japanese lower house (before playing) 2010/10/12 19 Role-holder Context Parliament Member of J. Lower House-xx Japanese Lower House Role-holder Parliament Member Constituent-xx vacant state Ico-1 Parliament Member Constituent Role-xx Person-abc × Ies-1 playing Instance of Post Role Role-playing thing Instance of Constituent Role J. Lower House Post Role playing Role-playing thing They are created by the predetermined quota (480). . . . . . . 480 There is no need to discuss in what order parliament constituent roles are created or what ID of them. It is different from the case of guest of restaurant. Role-holder Parliament Member of J. Lower House-zz playing Role-holder vacant state Parliament Member Constituent-zz Ico-480 We can’t identify particular vacancy. Parliament Member Constituent Role-zz Person-xyz × Ies-480 playing Role-playing thing Instance of Constituent Role Role-playing thing EKAW2010

22. One parliament member resigns Discussion:Parliament members(3/3) 2010/10/12 20 Role-holder Context Parliament Member of J. Lower House-xx 480 Japanese Lower House Role-holder Parliament Member Constituent-xx Ies-1 Parliament Member Constituent Role-xx Instance of Post Role Person-abc playing J. Lower House Post Role Role-playing thing Instance of Constituent Role Ies-1 playing Role-playing thing Unchanged in terms of Ies Different in terms of Ies Role-holder Parliament Member of J. Lower House-xx 480 Role-holder Parliament Member Constituent-xx Ies-x J. Lower House Post Role Parliament Member Constituent Role-xx Parliament Member Constituent Role-xx Person-abc Ies-1 playing playing Instance of Post Role Role-playing thing Instance of Constituent Role Role-playing thing EKAW2010

23. Characteristics of Instances Concerning Roles Represented using Four Kinds of Identities Instances of post role There is only one post role for each role concept in a context. We do not need todiscussIcofor it. It does not change for natural degradation as time goes by because it is immaterial unless the context changes its definition. It suggests that we don’t have to discuss Iexof post role. Instances of constituent role We can consider the essential property of each constituent role is determined by the event of any player’s participation in the context. We can distinguish between instances of constituent role by the time when it is created (in what order it is created) in terms ofIes. We can useIco if there is no need to discuss in which time and/or in what order they are created. e.g. parliament constituent roles. Creation of instances of constituent roles In the case where fixed number of roles are predetermined (e.g. parliament member) ->They are created in advance by that number and exist in vacancy. In the case of no predetermined quota (e.g. guests of a restaurant) ->They are created at the same time of new players’ participation. 2010/10/12 21 EKAW2010

24. Concluding Remarks Conclusion Considerations of 4 kinds of instance identities Identity for Exactness (Numerical identity) Identity for Essentiality Identity for Counting Identity for Replacement Identity of role concept post role vs. constituent role These considerations would provide a fundamental theory to discuss identity and contribute theoretically to instance management on computer system based on ontology. Future work Development of a theoretical framework for management of identity based on the consideration. Implementation of the framework in Hozo, an ontology building tool developed by us. 2010/10/12 22 EKAW2010

25. Acknowledgement 2010/10/12 23 EKAW2010 Thank you for your attention! Hozo are available at http://www.hozo.jp

26. A complicated problem of parts replacement of bikes 2010/10/12 24 EKAW2010 e.g. we assume two wheels as bike A’s essential property Different in terms of Ies Unchanged in terms of Ire Replacement of all parts except its two wheels Ies1 A Ies1 Ies3 A A’ Ire1 A Ire1 Ire1 Ies1 Ire1 B Ies2 Ies4（Ies1） B B’ Ire2 Ire2 Ire2 Make another bike using parts removed form A new two wheels are installed exchange the two wheels t1 t2 t3 t4 Different in terms of Ies Unchanged in terms of Ire we can deal with such complicated change of instances in each time points appropriately.

27. Identities of constituent role and post role Instances of post role It should correspond to a kind of specification of properties and functions of what a player is expected to play [Guarino 98, Massolo 04]. There is only one post role for each role concept in a context. We do not need todiscussIcofor it. It does not change for natural degradation as time goes by because it is immaterial unless the context changes its definition. It suggests that we don’t have to discuss Iexof post role. Instances of constituent role We can consider the essential property of each constituent role is determined by the event of any player’s participation in the context. We can distinguish between instances of constituent role by the time when it is created (in what order it is created) in terms ofIes. We can useIco if there is no need to discuss in which time and/or in what order they are created. e.g. parliament constituent roles. Creation of instances of constituent roles In the case where fixed number of roles are predetermined (e.g. teachers of a school) ->They are created in advance by that number and exist in unplayed states. In the case of no predetermined quota (e.g. guests of a restaurant) ->They are created at the same time of new players’ participation. 2010/10/12 25 EKAW2010

28. Classification of Identity(2) Synchronic and Diachronic Identities Synchronic identity Identity which represents the fact that two individuals are the same thing at a given time. e.g. “While one hour from 10:00 to 11:00 and one hour from 11:00 to 12:00 are different as a time interval, they are the sameas a quantity of time.” e.g. "the evening star and the morning star are the samestar, that is, Venus, though they have different names”. Diachronic identity Identity which discusses the sameness of instances at two time points. e.g. “Whether Taro, an instance of person, at present is the same person with the person five minutes ago or not ” e.g. “Whether an instance of bike and the bike some of whose parts are replaced are the same or not ” 2010/10/12 26 EKAW2010

29. Discussion:Parliament members(3/3) The house has dissolved 2010/10/12 27 Role-holder Context Parliament Member of J. Lower House-xx 480 Japanese Lower House Role-holder Parliament Member Constituent-xx Ies-1 Parliament Member Constituent Role-xx Instance of Post Role Person-abc playing J. Lower House Post Role Role-playing thing Instance of Constituent Role Ies-1 94th playing Role-playing thing The same in term of Ies Different in term of Ies Role-holder Parliament Member of J. Lower House-xx 480 Role-holder Parliament Member Constituent-xx Ies-x J. Lower House Post Role Parliament Member Constituent Role-xx Person-abc Ies-1 95th playing playing Instance of Post Role Role-playing thing Instance of Constituent Role non essential attribute Role-playing thing EKAW2010