2.3. DRM Abstract Model    (3YOU)

Figure 2-5 presents the DRM abstract model. It depicts the major concepts from each standardization area and the relationships between them. Concepts highlighted in red are described further below. Concepts are expressed as boxes, while relationships are expressed as arrows.    (3WZS)

http://colab.cim3.net/file/work/das/DRM_2.0/Figure_2_5.JPG    (3YOV)

The DRM abstract model is an architectural pattern to optimize agency data architectures. It is abstract in that it allows multiple technical implementations; for example, the Department of Defense could use the DOD Discovery Metadata Specification (DDMS) for Digital Data Resource attributes while another agency may choose to use the Dublin Core elements, and both could demonstrate how their implementation maps to the DRM abstract model. This architectural pattern is designed to optimize an agency’s data architecture for information integration, interoperability, discovery and sharing. The pattern achieves this optimization by defining, arranging and relating the standard concepts in a data architecture, specifying common attributes for each concept (presented in tables following the abstract model section figure in each chapter) and demonstrating a use case of the model in each chapter. Figure 2-5 depicts all the concepts and relationships in DRM the abstract model.    (3YOW)

Before defining each concept, it is important to understand the highlights of the model in the three standardization areas. In the Data Description standardization area, the focus is on understanding the data at two levels of abstraction: the metadata artifacts required to understand the data and how those metadata artifacts are aggregated into a managed Data Asset. There are two basic types of metadata recommended in the Data Description section of the DRM abstract model: logical data models to describe Structured Data Resources, and Digital Data Resource metadata (such as Dublin Core elements) to describe Semi-Structured and Unstructured Data Resources. The division of data along these two axes is intended to support harmonization (via comparison of logical data models) and registration (via description of universal resource attributes). Implementation of the Data Schema concept group would take the form of Entity-Relationship diagrams, class diagrams, etc. Implementation of the Digital Data Resource could be records in a content management system or metadata catalog.    (3WZV)

In the Data Context standardization area, the focus is on management mechanisms to capture the context of data in an organization or COI. Those mechanisms are Taxonomies (a hierarchical set of Topics connected by relationships) and a Data Asset description (captured in an inventory). A Data Asset is a collection of Digital Data Resources that is managed by an organization, categorized for discovery, and governed by a data steward. A key attribute of a Data Asset is whether it is authoritative and if so designated, authoritative on which Entity or Attribute of the logical data model (see Data Schema in the Data Description section of the DRM abstract model). Implementation of Taxonomies could take the form of extensible Markup Language (XML) Topic Maps, Web Ontology Language (OWL) hierarchies or ISO11179 Classification schemes. Implementation of a Data Asset inventory could be records in a metadata registry.    (3WZW)

Lastly, in the Data Sharing standardization area, the focus is on how information is packaged for and/or exposed to members of a COI. The key concepts are Exchange Packages as containers for fixed messages and Query Points as descriptions of data access points. Implementation of Exchange Packages could be standard XML messages or EDI transaction sets. Implementation of Query Points could be descriptions in a Universal Description, Discovery and Integration (UDDI) or ebXML registry of a data access Web service.    (3WZX)

Taken as a whole, the DRM abstract model should be used by agencies to assess the current state of their data architectures and to chart a roadmap to an improved architecture. In inter-agency collaborations, this abstract model becomes a Rosetta Stone to decipher specific implementations of these common concepts and thus speed effective communication to deliver cross-organizational agility to a COI.    (3WZY)

Subsequent chapters will “drill down” into the details of this abstract model. Chapter 6 also describes the DRM Abstract Model in its entirety. Each section of the DRM abstract model represents the core concepts and the relationship of those concepts within its respective standardization area. Each section represents the minimal level of detail necessary to convey the major concepts for the standardization area, with COIs extending the model as necessary for their implementations.    (3WZZ)