Building a Real World Semantics for MODAF Why MODAF needs a real world semantics

Building in a real world semantics (ontology) The real problem in speech is not precise language. The problem is clear language. Richard Feynmann Formal Semantics Real World IDEAS UML And if the language doesn’t provide a clear picture of the real world, how do people and machines know what is being talked about.

Ontology and the real world The question ontology asks can be stated in three words ‘What is there?’ and the answer in one ‘everything’. Not only that, “everyone will accept this answer as true” though “there remains room for disagreement over cases.” (Quine “On What There Is”). If you want a more technical definition An ontology is "the set of things whose existence is acknowledged by a particular … system." (E. J. Lowe, The Oxford Companion to Philosophy) So an ontology tells you the things that exist in the real world.

One real world: how many (UML compliant) entities? I This seems a reasonable entity But so do these And these All these are UML compliant.

One real world: how many (UML compliant) entities? II This seems a reasonable entity but they can they exist in the same model, it looks like two different ways to model address But so does this What about this? All these are UML compliant.

M3 starts to map the real world Problem is that the UML top level is not designed for real world semantics

Top level real world semantics UML was not designed to provide a real world semantics It has a formal semantics MODAF started to establish middle level real world semantics, within UML’s top level formal semantics Had to fit within the UML constraints MODAF as it currently stands has no top level real world semantics MODEM uses IDEAS (BORO) to bring these semantics in.

Build upon what already exists There is a significant investment in MODAF Harvest the relevant features Winnow out the irrelevant technical features

Building a semantic foundation implicit semantics From a semantic perspective, it is like an iceberg, with visible ‘explicit semantic’ and hidden ‘implicit semantics’. M3 was designed as a UML profile. The goal is to: Peel off the implementation structure, and Make the implicit semantics explicit semantic foundation M3 UML Profile implementation structure explicit semantics As a result it has both implementation structure and (explicit) semantics

Two examples Example 1 – SuperSubType Example 2 – Change over time - states

Real world semantics – example 1: super-sub-type

Recovering the supersubtype semantic structure MODEM superSubType is not the same as UML Generalisation.

Example 2: Change over time - states A UML State Machine Figure 15.12 - Protocol state machine” (p. 552 - UML Superstructure Specification, v2.3) This is one way UML can be used to represent change over time there are other ways to do this this can be used to represent most algorithms (abstract state machines)

What is ‘state’ in the real world? You can know the name of a bird in all the languages of the world, but when you're finished, you'll know absolutely nothing whatever about the bird... So let's look at the bird and see what it's doing — that's what counts. I learned very early the difference between knowing the name of something and knowing something. Richard Feynmann

UML States Have a very constrained structure. For example, cannot: Have a state inside more than one state machine Have one state machine inside another Subtype a state Why not? Can this happen in the real world (Yes!) Makes the formal structure easier (?)

Removing Implementation Structure Combining state machines State machine inside a state machine

Removing Implementation Structure Sub-typing state machines State subtypes another state State machine subtypes another state machine

Building in a ‘clear’ real world semantics IDEAS Real World UML Formal

More details concerning MODEM can be found at: http://www.amazon.co.uk/Business-Objects-Re-engineering-Chris-Partridge/dp/0955060303/ http://www.borosolutions.co.uk/research/content/files/SwAF-MODEM-Behaviour Analysis Report - March 2011.pdf http://dl.dropbox.com/u/823291/MODAF_M3_and_IDEAS_integration_phase%201%20and%202%20version_1.00.pdf http://dl.dropbox.com/u/823291/MODAF_M3_and_IDEAS_integration_examplification_version_1.00.pdf