Presentation on theme: "Copyright: SIPC Applying 4D ontologies to Enterprise Architecture Matthew West Reference Data Architecture and Standards Manager – Shell."— Presentation transcript:
Copyright: SIPC Applying 4D ontologies to Enterprise Architecture Matthew West Reference Data Architecture and Standards Manager – Shell
2 Abstract Enterprise Architecture is the term used for a number of related models that together describe an enterprise and its information systems. Many of these models are ontological in nature or have ontological content. A particular problem companies face is that historically many of their models have been "snapshot" or "current state" models and have not been able to manage the history of the enterprise, and of the models used to manage its information. With increasing regulation, such as Sarbanes-Oxley legislation,this is becoming an urgent problem. 4 Dimensionalism is a paradigm that sees objects as extended in time as well as space. As such it has history built in, using a "God's eye view" (outside time). Space-time maps are a technique for showing the patterns different sorts of individuals make in space-time and are a valuable aid to analysis. We will explore the use of these before looking briefly at one or two examples of how they have been used to develop and support Shell's Downstream (oil tanker to petrol pump) data model.
3 What is (an) Ontology? My Answer … Ontology is the study of what exists. An ontology is a theory of what exists. Doesnt have to be: Formal (computer interpretable) Use a particular form of logic Complete (fully axiomatised) Can be: Philosophical (sorts, identity criteria, lots of discussion) Artificial Intelligence, e.g. First Order or Description Logic based formal ontology. Database structure and data in a database
5 How are these ontologies held? Data Model Process Model Locations/Networks Organization/Workflow Events/Business cycles Business Rules Data Model Process Model Data Documents
6 The wider use of Ontologies beyond reasoning Language expressiveness Ontological Rigour SQLEntity Relationship OWL DLOWL FullFirst Order Logic Higher Order Logic Upper Ontologies Vast bulk of information systems Ontology limited or implicit Small number of sophisticated applications Small but increasing number of lower and mid level ontologies Huge potential to apply ontologies to traditional systems
7 So what are the practical problems Shell has been grappling with?
8 Differing data models for the same thing in different parts of Shell c1990
9 Data Model Notation: EXPRESS-G entity entity_x relationship STRING simple data type attribute entity_y Supertype relationship (subtype at circle end)
10 2. Cardinalities that lose history Sometimes cardinalities are set one-to-many (meaning one at a time), when they are really many-to-many because the relationship is transferable. Imposing restrictions through data structure means: – Arbitrary or inappropriate restrictions are placed on the data that can be held. – History data about a relationship cannot be held. – Data may be replicated to overcome the restrictions in the data structure. The different versions must be reconciled. – The entity type will only work within the context defined. A change in business rules may require a change in the database structure. – The resultant system is harder to share. This has only become more important with regulations like Sarbanes-Oxley (US accounting rules following the ENRON scandal)
11 Example: Ship What happens if you re-register a ship? Ship Port Name registered_at registered_under Transferable relationships
12 How can ontology help?
13 3D and 4D approaches to ontology Data model consistency is dependent on taking a common view of how to represent things across the business. Unfortunately there are many ways in which we can model the world. However, there are two main approaches, with on the whole minor variations, that dominate the philosophical literature. I will call these the 3D paradigm and the 4D paradigm.
14 3D Paradigm A 3D ontology treats physical objects (roughly things you can kick) as 3D objects (sometimes called continuants) that pass through time. The principles of the 3D paradigm are: 1. Physical objects are 3-dimensional objects that pass through time and are wholly present at each point in time. 2. Physical objects are viewed from the present. The default is that statements are true now. 3. Physical objects do not have temporal parts. 4. Different physical objects may coincide.
15 3D Individual time space The present (all that exists) Object passes through time.
16 4D Paradigm A 4D ontology treats all individuals – things that exist in space-time - as spatio-temporal extents, i.e. as 4D objects. The principles of the 4D paradigm are: 1. Individuals exist in a manifold of 4 dimensions, three space and one time. So things in the past and future exist as well as things in the present. 2. The four dimensional extent is viewed from outside time rather than from the present. 3. Individuals (including physical objects) extend in time as well as space and have both temporal parts and spatial parts. 4. When two individuals have the same spatio-temporal extent they are the same thing (extensionalism).
17 Possible Individual time space Object extended in time The past and the future exist as well as the present
18 Which paradigm? The 3D approach corresponds well with the way that language works. Language has a focus around here, now, you and me as a context, and on the current state of affairs. This leads to efficient communication under the most common circumstances. On the other hand dealing with change is relatively problematic. What is clear is that the 3D and 4D paradigms cannot be merged into a single canonical approach, since they are contradictory, with one requiring physical objects to have temporal parts, and the other forbidding them. On the other hand, it appears that what can usefully be said using one paradigm can generally be said using the other. For ISO (and Shells DDM) we chose the 4D paradigm because we found it to be rigorous, and gave a good account of some difficult cases.
19 Space-Time diagrams – an aid to analysis
20 State Time period Individual Possible Individual/State – Temporal whole-part time space Events
21 A B C D event 1event 2 Materialised Physical Object time space The Broom Head Handl e
22 A game of football – the ball time space Football Match 1 st Half 2 nd Half
23 A game of football – some players time space Football Match 1 st Half 2 nd Half Player 1 Player 3 Player 2 Owen Lampard Gerard Rooney Replaceable Parts Scattered parts Note: Some replaceable parts are roles Object continues
24 A game of football – Roles time space Football Match 1 st Half 2 nd Half Captain Owen Gerard Replaceable Part/Role Note: Some replaceable parts are roles
25 Your turn to do some work Draw one or more space time diagrams for the participants in the following end-to-end pump impeller replacement activity: A maintenance engineer requests purchasing to buy a new impeller for a pump. Purchasing order an impeller from the pump manufacturer sales dept. The pump manufacturer deliveries department delivers the impeller. The maintenance engineer replaces the pump impeller.
26 One I prepared earlier – Part 1 time space Supplier Organization Customer Organization End to end impeller replacement process Request Engineering Purchasing Delivery Sales Order Impeller Replacement Delivery
27 Pump No 3 One I prepared earlier – Part 2 time space Pump No 3 Impeller Impeller Replacement Engineering
32 Who is involved in Buying and Selling? Shells Downstream Data Model (DDM) has extended ISO from 201 entity types to more than 1700 Many different parties can be involved in buying and selling. Some of these parties are defined in the Organization schema – this is shown on the next slide
33 These subtypes give us some of the parties in buying & selling Buy and Sell parties class_of_participation_ of_responsible_individual business_role_in_ business_transaction 19,1 class_of_participation_ of_Shell_organization 20,1 class_of_supplier 20,2 class_of_customer participation_of_ responsible_ individual 17,1 Shell_business_partner stakeholder shareholder contractor 20,3 trading_party 23,5 employer 19,2 participation_of_Shell_ organization (RT) classified_by S[1:?] inspector goods_receipt_clerk dispatch_clerk dunning_clerk authoriser purchase_requisition_ authority purchasing_authority originator order_recipient manufacturer_ or_supplier buyer agent invoicing_party 21,1 relationship_ administrator 23,1 employee participating_part_of 2,1 responsible_individual
34 Summary Much business modelling has (or should have) ontology at its core Ontology has very wide applications – Ontology has been practised by many disciplines – The largest area for the application of ontology is in Business Information Systems The application of ontology can add considerable value to businesses