8. Naming Conventions

The Akoma Ntoso standard defines a number of referenceable concepts that are used in many situations in the lifecycle of legal documents. The purpose of this document is to provide a standard referencing mechanism to these concepts through the use of URIs associated to classes and instances of an ad hoc ontology. The referencing mechanism discussed in this document is meant to be generic and evolving with the evolution of the underlying ontology.

The most important concepts of the Akoma Ntoso ontology are related to documents that have legal status. All discourse and all description of legal sources can be characterized as referring to one of the four levels of a document as introduced by IFLA FRBR (International Federation of Library Associations (IFLA) - Functional Requirements for Bibliographic Records (FRBR) http://www.ifla.org/VII/s13/frbr/frbr.pdf):

• WORK: the abstract concept of the legal resource (e.g., act 3 of 2005)
• EXPRESSION: any version of the WORK (whose content is specified and different from others for any reason: language, versions, etc.)
• MANIFESTATION: any electronic or physical format of the EXPRESSION: word, xml, Tiff, pdf, etc.
• ITEM: physical copy of any manifestation in the form of a file stored somewhere in some computer on the net or disconnected.

All levels but WORK can be composed of sub-elements:

• ExpressionComponent: (main, schedule, table, etc.) - the ExpressionComponents represent the visible division of the document as generated by the content author (Parliament, etc.)
• ManifestationComponent: (xml files, PDF files, TIFF images, etc.) - the ManifestationComponents represent the division of the document as generated by the manifestation author (e.g., the XML editor).
• ItemComponent: (the actual files corresponding to the ManifestationComponents)

Other concepts dealt with the Akoma Ntoso ontology also derive from the IFLA FRBR ontology, and include but are not limited to individuals (Person), organizations (Corporate Body), actions and occurrences (Event), locations (Place), ideas (Concept) and physical objects (Object).

Scope of the naming convention is to identify in a unique way all Akoma Ntoso concepts and resources on the net and in general all collections thereof. Some principles and characteristics should be respected in the naming convention:

• MEANINGFULNESS: the name is a meaningful and logical description of the resource and not of its physical path
• PERMANENCE: it shall be permanent and stable over time
• INVARIANCE: it shall derive from the invariant properties of the resource so as to provide some degree of certainty in obtaining the same name for the same resource regardless of process, tool and person.

URIs are used in a variety of situation. In each cases it is important to use the URI for the correct level of document. We introduce here a few particularly frequent situations:

1. Legislative references will most probably refer to WORKs: acts referring to other acts do so regardless of the actual version, and references must be to something independent of all possible expressions, .e., the work.
2. The list of attachments and schedules belong to a specific EXPRESSION, so references to ExpressionComponents is specific of the expression level.
3. Yet the specific Manifestation that is the Akoma Ntoso XML format uses an XML-based syntax to refer to ExpressionComponents, and associate them to the corresponding ManifestationComponents containing the appropriate content. Therefore within XML files the URI of the ManifestationComponents must be used to refer to all components, including the main document, all attachments and all schedules.
4. Multimedia fragments within an XML manifestation (e.g., a drawing, a schema, a map, etc.) do not exist as independent ExpressionComponents, as they are only a part of the ExpressionComponent (even when they are the only part). In fact they are only ManifestationComponents, and as such are referred to in object and img elements with the appropriate ManifestationComponent URI. Even if the same multimedia content appears in different parts of the content of a Manifestation, each instance of that content must correspond to a different ManifestationComponent, and must be considered independently of the other.
5. It is a Item-level decision, once ascertained that the content is exactly identical, to provide space-saving policies by storing only one copy of the multimedia content. This Item-level decisione has no impact on references and names, which are still individually different from each other.
6. Non-document concepts are referred to within the metadata and content of Akoma Ntoso documents. References are always performed in two steps: the first step ties the reference point in the document to an item in the Reference section using internal (and not standardized) IDs; the second step ties the item in the reference section to the actual concept through the URI of the concept as specified in this document.

Since the most important concepts in Akoma Ntoso are connected to documents, the main part of this documents are devoted to specifying the URIs of document-related concepts, and in particular Works, Expressions, and Manifestations. Items are by definition outside of the scope of this document, and are only briefly described. The final part of the document provides a URI-based naming mechanism for non-document entities (as well as for document entities that are handled in a similar way to non-document entities).