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Data with destiny and our latest data sets Manchester. Neural Designer - Download. One improvement proposed by Mitchell and Panzer is a set of links from the Dewey geographical terms to GeoNames. If the same change were applied to the DDC, articles published with New York Times headings could be discoverable through Dewey classes. The DDC model demonstrates that SKOS is not rich enough to capture all of the information in a library authority file, even when the focus is restricted to models of topical subject headings.
Although SKOS lacks some important granularity, the conversion process first defined by the Summers team is both explicit and simple enough that nearly anyone with self-taught scripting skills and access to a MARC compliant authority file can conduct experiments capable of producing mature results. The most important outcome of this work is that it is now technically feasible to record the subject of a book by embedding a URI instead of the literal string, thus sidestepping the problems with maintenance and data quality mentioned in the opening paragraphs of this chapter.
The most important outcome of the projects described in this section is a set of first-draft RDF datasets generated from legacy library authority files. Because of the close fit between the MARC Authority format and the SKOS ontology, the conversion process is well-understood and mechanical, if certain requirements are met: the source dataset has a thesaurus-like structure, there is a one-to-one relationship between a concept definition and a database record, and the record has a persistent identifier that can be repurposed into a globally unique URI.
But only the largest and most widely used library authority files have been converted to RDF. The new format offers the promise that library authorities can be integrated more deeply with the broader Web, while raising questions about the appropriateness of the thesaurus model for referents that are physical or tangible objects in the real world.
As the discussion has shown, the conversion of a name authority record from MARC to SKOS has simply moved the problems in the original specification to the new format. In particular, SKOS is still a model of curated strings. This problem is addressed in FOAF, though only partially, because the ontology does not define a death date. In addition, FOAF does not support a well-rounded description of a person with multiple identities or personas.
Of course, Samuel Longhorne Clemens might be viewed as an outlier in the literary canon because he wrote under multiple pseudonyms. The Virtual International Authority File, or VIAF, merges the data maintained in the most widely used library authority files and makes the results available to a worldwide audience of data consumers. Thus VIAF was designed to reduce the cost of library authority control through collaborative effort, creating more reliable links to, from, and among library resources.
Since , VIAF has been managed as an international consortium. In July , the VIAF Consortium had participants from 29 countries, representing 24 national libraries and 14 other agencies. At that time, the VIAF database contained 35 million personal names, over 5 million corporate names, nearly a half million geographic names, and over two million standardized or uniform titles, or names of creative works OCLC a.
The result was a dataset containing 9. Since its initial release, the VIAF RDF dataset has undergone many updates and modifications that align it more closely with the standards and best practices emerging from the linked data community. Some of the changes have been technical or stylistic, but the most fundamental change is the same one that affected the other models of library authority files we have surveyed so far in this chapter.
Like FAST—and to some extent, the Library of Congress authority files—the current RDF version of VIAF is now less about curated strings for the names of concepts and more about the real-world entities whose importance has been recognized by librarianship. The complete list of preferred forms is shown in the second segment and the interconnections that have been computed by the VIAF clustering algorithms are depicted in the starburst pattern on the right.
Starbursts representing internationally important historical figures such as Mark Twain are especially dense because their works are widely translated and held in libraries all over the world. The last segment preserves the revision history of the VIAF identifier. Since the contents of the record are assembled from inputs provided by third parties, the identity may not be stable if it is computed from sparse or noisy data. The clustering algorithms are tuned to make conservative decisions and may produce multiple VIAF identifiers for the same individual in these circumstances, which can be merged when more data becomes available.
This segment makes it possible for a human or machine process to follow the path from a deprecated identifier to the current one. Such a custom design is necessary, because no existing standard adequately represents the semantics of an aggregated authority file. But the preferred headings are coded as fields instead of fields because the MARC 21 Authority standard permits multiple fields but only a single field per record. In addition, the identifier is preceded by a two- or three-letter acronym for the name of the source authority, a mnemonic for the human reader or software process.
This example provides a glimpse of the large and rich VIAF database record structure, which is designed to merge library authority files developed by different national libraries into a single hub of authoritative information expressed in multiple languages and character sets.
This book gives an overview of the principles of Linked Data as well as the Web of Data that has emerged through the application of these. Just as hyperlinks in the classic Web connect documents into a single global information space, Linked Data. Linked Data: Evolving the Web.
A human reader can make the stronger inference that all three identifiers refer to the same unique real-world individual, but a more sophisticated data model is required before a machine process can do the same. But it is enhanced with an explicit reference to the world beyond the text. Many of the statements in the first block describe Mark Twain using properties from Schema.
These terms are definable as additional properties for the schema:Person class, have yet not been published in BiblioGraph because the model of a literary persona is still being developed. They have the same internal structure. First, an entity represented in the authority file is associated with a URI. If the source authority file has been modeled as RDF by a recognized maintenance agency, the block contains a skos:exactMatch statement with a URI from the source. At the center is the core entity schema:Person , and on the periphery is a set of descriptions obtained from the aggregated authority files.
The grayed-out elements describe the form and provenance of the source strings in essentially the same terms as the current version. Though the links between the skos:Concept layer and the viaf:NameAuthorityCluster are arguably more straightforward in this model, the design was abandoned. Even so, the statements containing skos:prefLabel were available only in the source authority descriptions, not in the hub, requiring a machine process to traverse the RDF graph to locate them.
But a model with this detail required an additional class, skosxl:Labels Miles and Bechhofer a , an extra URI pattern that differentiated the VIAF identifier from the string label, and a retrospective conversion that was not guaranteed to be reliable. As a result of the revision of the previous model to the current one, the referent for the canonical VIAF identifier changed from an artificial construct to a real-world object.
This was a radical shift that positioned VIAF to evolve into an authoritative hub of data—primarily about people, but also about a small number of places, organizations, and works—which is managed by the library community in a format that can be consumed by the broader Web.
The change marked a bold departure from legacy library standards, a change that was bound to happen, because the MARC 21 Format for Authority Data was never a good fit for the semantics of a trans-national aggregation.
Anticipating the subject of the next chapter, we note here that the description of creative works is the focus of much experimentation by OCLC researchers. Here it is a schema:CreativeWork instead of a schema:Person , with properties such as schema:name , schema:alternateName , schema:author , and schema:inLanguage. By mining WorldCat for evidence of translations such as this one, we can expand the scope and depth of Work descriptions in VIAF well beyond the baseline contributed by human catalogers.
Other users can improve or add to this information CKAN keeps a fully versioned history. CKAN powers a number of data catalogues on the Internet. The Data Hub is an openly editable open data catalogue, in the style of Wikipedia. There is a comprehensive list of catalogues like these around the world at datacatalogs.
CKAN is the open-source data portal software. CKAN makes it easy to publish, share and find data. It provides a powerful database for cataloging and storing datasets, with an intuitive web front-end and API.