Knowledge representation based on experiences of metamodel-based architecture modeling and nadural language dictionaries.

(No point to look at the code. This project is long abandoned, if the folowing gets implemented that will probably be done in another project. I am just using this README to write up my thoughts.)

Dictionaries for natural languages are hard to implement for the following reasons:

1. A word usually have different meanings
2. How do you describe the meaning of a word? The best approach so far is that of wordnet: you basically define relationships between words.

Metamodel-based architecture modeling works like this:

1. You come up with metamodel elements. You define those elements through their possible relationships, and the constrainst on those relationships. Note that this fully defines the metamodel element for all purposes within the model itself.
2. You use these metamodel elements to define actual model elements.

A metamodel is basically the language used to describe the model. When you define a metamodel element, nothing stops you to give it the same name as another metamodel element, apart obvious useability considerations. Architecture models however operate on a limited domain. Natural languages - oerating on unlimited domain - have different useability considerations, thus they do have words describing different meanings. Note that even if you have two metamodel elements with the same name, their ID will still be different.

In the model Used by Zenta metaamodel elements and relationships are explicitly marked as such, and that marking is somewhat cumbersome (is something appears in a view marked as Template, then it is a metamodel element). This is however an arbitrary limitation. Other ontology models (like Protégé) do not have this.

From the practical standpoint the most important limitation is that a relationship can only be between two elements in Zenta. Natural languages do not have this limitation: e.g. the word 'give' describes a relationship between the person who gives, the object which s given, and the person to whom the object is given to.

But natural languages are very hard to process automatically, so they are not adequate to use for architecture modeling.

Note that architecture modeling is nothing else than the definition of a domain specific language, and the representation of knowledge about that specific domain. And a good architecture modeling tool can be used to describe any domain, so it is not domain specific itself.

But there is a language which is designed to be spoken, still convey precise meanings, based on predicate logic: Lojban.

In Lojban, sumti is the same thing as a (metamodel) element in an architecture model. And bridi is the construct which describes relationships, between any (practically up to 5) sumtis.

So the model is the following:

A sumti have an id and a string representation.

A bridi have an ID and a tuple of sumties. The first of them is the meaning of the bridi, the rest of them are its "arguments".

Well actually everything in the model has an ID, a string representation, and zero or more reference to other stuff in the model. If there are zero references, we call it a sumti, if there are more, it is a bridi.

A bridi's string representation is computed using messageFormat(sumti1,...sumtiN).

As an illustration, some of the first sumties defined will probably be

• thing
• {1} is a {2}
• sumti
• bridi

So the bridi ({1} is a {2}, sumti, thing) will have the string representation sumti is a thing.

Well, probably someone will make sumties with string representation using actual lojban (spanish, german, etc...) words at a point, but my goal here is just to use the structure, and not interested in actually learning yet another language (Javascript was big enough trauma already).

Implementing inference and the usual predicate logic stuff based on this representation should be straightforward to anyone knowing how to do that.

Diagrams in architecture models are already described using models. As soon as they are metamodeled, they can be stored in the same storage.

The same is true for constructs used to structure models (e.g. folders), and for access control.

Version control and support for multiple repositories - with models referencing sumties/bridis from other repositories however should be embedded in the model. For that purpose a full ID is in the form <repository>:<id>:<version>.