Once a data provider has decided to publish a bibliographical database as Linked Data, there are important components that should be considered, including:
1. What kinds of entities and relationships are involved in describing and accessing bibliographic resources?
LODE-BD believes that a conceptual model would help to establish an overall picture of involving entities and relationships in bibliographic descriptions. In a broader context, the use of a similar conceptual model among data providers should also help foster a common understanding of the involving data models. Thus, LODE-BD uses a simple conceptual model based on three entities: resource, agent and thema. Major relations can be identified between a resource instance (e.g. an article or a report) and the agent(s) (e.g. a personal author or a research team) that are responsible for the creation of the content and the dissemination of the resource, as well as the thema(s) (e.g. things that being the subjects or topics of an article). The model provides sufficient capabilities for data providers to present their content (such as in document repositories and library catalogues) for sharing in the traditional environment or transferring to the Linked Data environment. (See explanations in a separate deliverable Meaningful Bibliographic Metadata (M2B)).
2. What properties should be considered for publishing meaningful/useful LOD-ready bibliographic data?
In the Linked Data context any data provider can expose anything contained in its local database. However, in the case of bibliographical data, standardized types of information should be considered in order to maximize the impact of sharing and connecting of the data. LODE-BD has built its recommendations on nine groups of common properties for describing bibliographic resources (details explained in M2B). These include specific best practice recommendations for about two-dozen properties used for describing a bibliographic resource as well as an additional two sets of properties for describing relations between bibliographic resources or between agents.
3. What metadata terms are appropriate in any given property when producing LOD-ready bibliographic data from a local database?
LODE-BD has selected a number of well-accepted and widely used metadata/vocabularies and used their metadata terms in the recommendations. All metadata terms used in the Recommendations are included in a crosswalk table (refer to Section 2.2). Flowcharts are used to present individualized decision trees, which provide adjustable decision process to data providers and for their situations when selecting metadata terms (refer to Section 3).
The comprehension of all the components below should enable a data provider to carry out the selection process of the metadata terms that fit in his bibliographic data requirements.
All metadata terms corresponding to the properties grouped by LODE-BD are presented in the following crosswalk. Usually metadata terms from the Dublin Core namespaces are the fundamentals, while metadata terms from other namespaces are supplemented when additional needs are to be satisfied. They are:
The semantics of the metadata terms (e.g. definition, usage, and relation with another property) defined by these specifications are inherited when a recommendation is made in a decision tree.
Table 2. Crosswalk of metadata terms used in the LODE-BD Recommendations