Proposed changes to the data model of ISO 15926-2

Introduction

Below is a diagram that is a combination of diagrams 6, 7 and 8 of ISO 15926-2:

In practice there are a number entity types missing, and these have to be added by reference data. That weakens the strong basis of Part 2.

Proposed changes

Below is a diagram that is a combination of diagrams 6, 7 and 8 of ISO 15926-2:

Proposed schema for PossibleIndividual and ClassOfIndividual in Part 2

The blue boxes are new, the pink box and the subtype links have been moved. The reasons for this are given below.

New Kids-on-the-block

Symmetry where possible

The asymmetry of the present model does not help to easily understand it. The proposed schema brings that symmetry, where possible. The added entity types are:

Subtypes of ArrangedIndividual

The proposed new subtypes of ArrangedIndividual are:

• Organism: "An <organism> is a <physical_object> that is living."
• Person: "A <person> is an <organism> of the species homo sapiens."
• InanimatePhysicalObject: "An <inanimate_physical_object> is a <physicsal_object> that not is living."
• Energy: "An <energy> is a <physical_object> that is capable to perform work." (questionable)
• Feature: "A <feature> is a <physical_object> that is a contiguous, non-separable part of some <physical_object> and has an incompletely defined boundary."
• GeometricalSolid: "A <geometric_solid> is a <physical_object> that is the space occupied by a physical solid."
• FunctionalObject: "A <functional_object> is a <physical_object> that has functional, rather than material, continuity as its basis for identity."
• Organization: "An <organization> is a <physical_object> that is composed of temporal parts of people and other assets, and is organised with a particular purpose."
• InformationObject: "An <information_object> is an <arranged_individual> that is presents and represents information."

Subtypes of ClassOfArrangedIndividual

The proposed new subtypes of ClassOfArrangedIndividual are:

• ClassOfPhysicalObject: "A <class_of_physical_object> is a <class_of_arranged_individual> whose members are instances of <organism>, <inanimate_physical_object>, or both."
• ClassOfStream: "A <class_of_stream> is a <class_of_physical_object> whose members are instances of <stream>."
• ClassOfEnergy: "A <class-of_energy>  is a <class_of_physical_object> whose members are instances of <energy>."
• ClassOfSpatialLocation: "A <class_of_spatial_location> is a <class_of_physical_object> whose members are instances of <spatial_location>."
• ClassOfGeometricSolid: "A <class-of_geometric_solid> is a <class_of_physical_object> whose members are instances of <geometric_solid>."
• XmlSchemaDataType: "An <xml_schema_data_type> is a <class_of_information_representation> whose members are instances of XML Schema data types."

Deprecated entity types

The following entity types could be deprecated: MaterializedPhysicalObject, FunctionalPhysicalObject, ClassOfExpressInformationRepresentation, and RepresentationOfGregorianDateAndUtcTime. Throwing away these entities requires an explanation of how their present semantics would be expressed in the proposed schema.

Please note that the subtypes of the present PossibleIndividual are not in a ONEOF mode. This is not an oversight, but has been done on purpose. It allows for the construction of more complex entities, whereby combinations of two or even more entity types can be made.

Functional- and MaterializedPhysicalObject

These two entity types have been created in 1996 in an attempt to bridge the gap between the believers in the erstwhile "Facility" and the non-believers. But this compromize has not ended the debate.

The FunctionalPhysicalObject has the following definition: "A FunctionalPhysicalObject is a PhysicalObject that has functional, rather than material, continuity as its basis for identity." . The proposed FunctionalObject would have a definition like: "A FunctionalObject is an PhysicalObject that has functional, rather than material, continuity as its basis for identity." EXAMPLE An AND gate.

If one has to create a function diagram, such as a Logic Diagram for a shutdown system, he/she can do that with that with FunctionalObjects. The material realization of these functional objects takes place by using instance of PhysicalObject that has the proper functional aspects.

ClassOfExpressInformationRepresentation and RepresentationOfGregorianDateAndUtcTime

The use of these entity types creates problems, because they are not mainstream. The XML Schema data types are.

Moving subtype links

ClassOfInanimatePhysicalObject, ClassOfActivity, etc are subtypes of ClassOfArrangedIndividual. But PhysicalObject, Activity, etc are, at present, not subtypes of ArrangedIndividual. This is illogical. Therefore these subtypes of PossibleIndvidual are proposed to become subtypes of ArrangedIndividual.