Reference Model. Definition, characteristics, uses and two examples close to GSIM

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1 Reference Model Definition, characteristics, uses and two examples close to GSIM

2 Reference Model (OASIS) (Organization for the Advancement of Structured Information Standards) An abstract framework for understanding significant relationships among the entities of some environment, and for the development of consistent standards or specifications supporting that environment. A reference model is based on a small number of unifying concepts and may be used as a basis for education and explaining standards to a non-specialist. A reference model is not directly tied to any standards, technologies or other concrete implementation details, but it does seek to provide a common semantics that can be used unambiguously across and between different implementations

3 Some characteristics (Wikipedia) Entities and relationships: A reference model contains both entities (things that exist) and relationships (how they interact with one another). A list of entities, by itself, is not sufficient to describe a reference model. Technology agnostic: A reference model is not useful if it makes assumptions about the technology or platforms in place in a particular computing environment. A reference model is a mechanism for understanding the problems faced, not the solutions involved, and as such, must be independent of the selected solutions in order to provide value to the practitioner.

4 Uses of a Reference Model (Wikipedia). One use is to create standards for both the objects that inhabit the model and their relationships to one another. By creating standards, the work of engineers and developers who need to create objects that behave according to the standard is made easier. 2. Using a reference model, leaders in software development can help break down a large problem space into smaller problems that can be understood, tackled, and refined. Developers who are new to a particular set of problems can quickly learn what the different problems are, and can focus on the problems that they are being asked to solve, while trusting that other areas are well understood and rigorously constructed. The level of trust is important to allow software developers to efficiently focus on their work. 3. A third use of a reference model is to improve communication between people. A reference model breaks up a problem into entities, or "things that exist all by themselves." This is often an explicit recognition of concepts that many people already share, but when created in an explicit manner, a reference model is useful by defining how these concepts differ from, and relate to, one another. This improves communication between individuals involved in using these concepts.

5 Uses (continued) 4. A fourth use of a reference model is to create clear roles and responsibilities. By creating a model of entities and their relationships, an organization can dedicate specific individuals or teams, making them responsible for solving a problem that concerns a specific set of entities. 5. A fifth use of a reference model is to allow the comparison of different things. By breaking up a problem space into basic concepts, a reference model can be used to examine two different solutions to that problem. In doing so, the component parts of a solution can be discussed in relation to one another.

6 Related Example MetaNet Reference Model (2003) A reference model is a model that allows mapping different metadata models to an agreed common model. The mapping to the reference model is made by means of concepts, i.e. similar concepts are mapped to each other. Hence, the reference model is mainly based on conceptual definitions of statistical metadata on different levels. How detailed a reference model is defined depends on the goal of the reference model. When we are going to define a reference model that allows mapping metadata models in detail the reference model itself must provide definitions for detailed concepts. On the other hand the reference model must be independent on any implementation issue, i.e. it must be possible to map relational models as well as to object-oriented models or to any other modelling approach. 00+ objects in MetaNet Reference Model, 85 pages in specification.

7 Example Process & Operations Region rule rule MatrixOperation arguments result Matrix input result StatisticalProcess OperationImplementation Dataset arguments RecordType result RecordReference input output ProcessImplementation parameters parameters sources RecordVariable parameters ComputationRule arguments result rule ComputationImplementation ProductionSystem ContextDataElement sources result

8 Lessons learned from MetaNet?

9 OAIS Reference Model (Open Archival Information System)

10 The OASIS Reference Model provides a framework for the understanding and increased awareness of archival concepts needed for long term digital information preservation and access. provides the concepts needed by non-archival organizations to be effective participants in the preservation process. provides a framework, including terminology and concepts, for describing and comparing architectures and operations of existing and future archives. provides a framework for describing and comparing different long term preservation strategies and techniques. provides a basis for comparing the data models of digital information preserved by archives and for discussing how data models and the underlying information may change over time. provides a foundation that may be expanded by other efforts to cover long-term preservation of information that is not in digital form (e.g., physical media and physical samples). expands consensus on the elements and processes for long-term digital information preservation and access, and promotes a larger market which vendors can support. guides the identification and production of OAIS-related standards.

11 Summary Reference models are only useful if they are used actively for reference. Reference models are best implemented through standards IF relevant standards do not already exist they should be developed based on the reference model Where existing (implicit or explicit) models have been implemented they can be mapped to the reference model for comparison/interoperability. If an implementer is free to choose their model, apply the reference model directly (via standards)