Support Files For "Easy RDF For Real-Life System Modeling"

The RDF DTD

The DTD file defines all the external modules (external entities) and shortcuts (internal entities) that are used to make the RDF easier to create and read.

The Main RDF-XML File

The main RDF file acts as a kind of driver, since it specifies which external modules (entities) to load. Note that it is short and simple, since it only orchestrates the import of other modules.

The Fully-expanded RDF-XML File

The fully-expanded version of the RDF-XML file contains the contents of all the external modules. All the shorthand internal entities have also been expanded. This is the version that you would check with the RDF validator.

The easiest way to produce the fully-expanded file is to run the RXP parser against the main RDF file. You can re-direct the output to a file. Do note that the output of RXP will contain a DOCTYPE declaration pointing to the DTD. Since the DTD is not complete, some processors may have trouble with it. It is better to delete this DOCTYPE declaration, since at this point the DTD does not contain any information that is not already in the expanded RDF file.

The *.ent Files

These files are the external entities that get imported by the main RDF-XML file. They are fragments of RDF-XML. All the content could have been put into a single file, but this manner of modularizing makes creation and maintenance of the data much easier.

• basemodel_ontology.ent defines Classes and ObjectProperties. At an early stage of modeling, the main value is to provide text labels for the classes.
• definitions.ent defines additional classes or properties (which could have been put into basemodel_ontology.ent).
• orgs.ent contains instance data for the various organizations in the data set.
• persons.ent contains instance data for persons in the data set.
• systems.ent contains instance data for the systems in the data set.

The *_ent.txt Files

These files are simplified versions of the external entitiy files. They contain a variety of structured text. Although one can write the RDF-XML modules by hand, it is easier to write this textual format. These files are converted to the *.ent (RDF-XML) files using a simple Python parser. The file naming convention makes it easy to convert all the files using a batch process.

The great virtue of using this textual format is that it is very close to the way most people would automatically jot down the information.

• basemodel_ontology_ent.txt generates basemodel_ontology.ent
• definitions_ent.txt generates definitions.ent
• orgs_ent.txt generates orgs.ent
• persons_ent.txt generates persons.ent
• systems_ent.txt generates systems.ent

HTML Files

These files illustrate different ways to display the data. They were generated from the main RDF file using the XSLT transformations linked in the next group.

Note that these XSLT transformations work because of the carefully chosen structure of the RDF-XML files. There are different structures that would be perfectly valid in RDF-XML, but would not work with the XSLT files.

• listing.html is a display of all the instance data in the data set.

• template.html is an example template that shows the structure without any data filled in. Each kind of object in the data set is shown with all the properties that are actually used, even if some properties are used in one instance but not another. Properties are not duplicated. For example, only one related-person is shown, even if some System should contain more than one.

  Such templates can easily be turned into word processing documents or on-line forms, to be used for collecting data to populate the model.

• classes.rdf.html is a display of all the class hierarchy. It is constructed by looking for all top-level owl:Class elements.

• props.rdf.html is a display of all the properties used by each class. It is not necessary to define them in an ontology. The XSLT transformation looks for those properties actually used, whether or not they have been defined anywhere, and whether or not they have been assigned to a class by a range or domain specification. However, labels (rdfs:label properties) are not included in the listings.

  Note that the transformation displays nested properties to any depth.

The XSLT Style Sheets

These are the style sheets I used to transform the RDF-XML data into the various HTML views.

• arch_display.xslt produces the display of all the instance data, as shown in listing.html.
• arch_template_skeleton.xslt produces the data template, as shown in template.html.
• class_hierachy_listing.xslt produces the data template, as shown in classes.rdf.html.
• class_properties_listing.xslt produces the listing of all class properties, as shown in props.rdf.html.