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PRISM
Like all media organizations, NewsLine wants to repurpose content in order to get a greater return on the investment made in creating it. Apart from first-use sales, the same material might be used in special packages for use by customers in later publication issues, such as in a topic retrospective or a photo series on a prominent individual. The company needs an approach that supports discovery by customers, rights tracking, and end-to-end meta data in the business process. Most published content already has meta data created for it. However, once content moves between systems in the information flow, the meta data is frequently discarded, only to be re-created later. The service has therefore decided to base their system on the PRISM standard for describing their stories.PRISM is a specification developed by the publishing industry representatives. It defines a meta data vocabulary for syndicating, aggregating, and multipurposing content over a wide range of publication types. PRISM provides XML elements for the topics, formats, genre, origin, and contexts of a resource. It also provides for categorizing resources, using multiple subject description taxonomies. An important feature of the specification is its use of other standards: XML, RDF, Dublin Core, as well as various ISO formats and vocabularies. You can see details of PRISM 1.2 at [www.prismstandard.org/.]
Dublin Core Elements
In Chapter 3 we introduced the Dublin Core Metadata Initiative (DCMI) vocabulary for the form definition examples, so you’ll be familiar with several elements by now. The core elements provide us with “pidgin” meta data terms that can be extended for requirements that are more specialized. As well as the core elements listed in the table that follows, DCMI also specifies a range of qualifiers that either refine the meaning of a core element or extend the vocabulary. For example, dc:date may be qualified to dc:created, dc:modified, or dc:issued.The recommendation also covers encoding schemes that specify formats for values such as date, language, and country, or that define controlled vocabularies for place names or categories.The table lists the 15 core elements in the dc namespace.
Element | Definition |
|---|---|
dc:identifier | Identifier(s) for the resource. |
dc:title | The name by which the resource is known. |
dc:date | The date of publication or availability of the resource. The recommended format of the date is yyyy-mm-dd, where dates are encoded with the W3C Encoding rules—a profile based on ISO 8601. See Date and Time Formats, W3C Note, [www.w3.org/TR/NOTE-datetime]. |
dc:creator | The primary creator(s) of the intellectual content of the resource, so it covers roles like composer, photographer and artist as well as author. |
dc:contributor | Additional contributors to the creation or publication of the resource, such as editor or translator. |
dc:description | A description of the resource. |
dc:language | The principal language of the resource. |
dc:format | The file format. DCMI recommends using the Internet Media Type (IMT) of the file. You can read about IMT values at [www.isi.edu/in-notes/] iana/assignments/media-types/media-types. |
dc:type | Defines either the genre, or intellectual type, of the resource or its presentation. |
dc:publisher | An identifier for the supplier of the resource. |
dc:source | An identifier for source material for the resource, assuming it is derived from another format. |
dc:coverage | Indicates geographic locations or periods of time that are subjects of the resource. |
dc:subject | The subject of the resource. |
dc:rights | Container element for specific rights data. |
dc:relation | A reference to a related resource. |
PRISM Elements
PRISM uses the Dublin Core element set as the foundation for its meta data. PRISM recommends practices for using the vocabulary and also augments it to allow more detailed descriptions. The augmentations are defined in three new namespaces.prism is the main namespace. Most of its elements are more specific versions of elements from the Dublin Core. For example, dc:date is extended by elements like prism:creationTime and prism: publicationTime. Here is a selected list of elements.
Element | Definition |
|---|---|
prism:category | The genre of the resource, such as election results vs. biographies. |
prism:distributor | An identifier for the distributor of the resource. |
prism:edition | An identifier for geographic or demographic versions of an issue. |
prism:issn | ISSN for the publication. |
prism:number | Part of volume and number identification for resource’s publication. |
prism:startingPage | Initial page number for the resource in its publication. |
prism:volume | Part of volume and number identification of the resource’s publication. |
prism:issueName | An identifier for named issues. |
prism:creationTime | Date and time the identified resource was first created. |
prism:modificationTime | Date and time the resource was last modified. |
prism:publicationTime | Date and time when the resource is released to the public. |
prism:receptionTime | Date and time when the resource was received on current system. |
prism:event | An event referred to in or described by the resource. |
prism:industry | An industry referred to in or described by the resource. |
prism:location | A location referred to in or described by the resource. |
prism:person | A person referred to in or described by the resource. |
prism:organization | An organization referred to in or described by the resource. |
prism:section | The section, such as “news,” “politics,” and so on in which the resource might be placed. |
Using keywords for describing the subjects of a resource rarely works well, because different people will use different keywords for the same subject. The recommended practice is to code the meta data from a well-defined set of subject terms that provide a common ground for both searcher and indexer. The PRISM Controlled Vocabulary, or pcv namespace, provides elements for specifying terms in a vocabulary, the relations between terms, and alternate names for the terms.
pcv:broaderTerm | Links to a broader (more general) concept in a vocabulary—for example, from “Dog” to “Mammal.” Multiple broader term links are allowed. |
pcv:code | Provides the unique identifier for the term. |
pcv:definition | Provides a human-readable definition for the item in the vocabulary. Multiple definitions can be provided with different language attributes. |
pcv:Descriptor | Grouping element for the information describing or defining a term. The definition must include a unique URI reference so that the term can be unambiguously identified. |
pcv:label | Provides a human-readable label for the preferred name(s) of the term. Multiple labels can be provided, usually with different language attributes. |
pcv:narrowerTerm | Links to a narrower (more specific) concept in the vocabulary. For example, from “Dog” to “Dalmatian.” Multiple narrower term links are allowed. |
pcv:relatedTerm | Links to a related term in the vocabulary, where the nature of the relation is not specified. |
pcv:synonym | Provides alternate labels (synonyms) for the same property. |
pcv:vocabulary | Provides a human-readable name identifying the vocabulary from which the term comes. |
Knowing the rights status of material can be a problem for everyone in the supply chain. There is a number of proposals for rights management languages, but there is as yet no industry agreement on which proposal to accept. Some are very complex, supporting a wide range of rights transactions.PRISM provides elements for basic tracking of rights. PRISM Rights Language (PRL), using the prl namespace, was defined to provide simple elements that let people say if an item can or can’t be used, depending on conditions of time, geography, and industry. Several prism namespace elements are also relevant to rights issues.
prism:copyright | A copyright statement for this resource. |
prism:expirationTime | Time at which the right to reuse expires. |
prism:releaseTime | Time as which the right to reuse a resource begins, and the resource may be published. |
prism:rightsAgent | Name and contact information of a rights agent. |
prl:geography | Specifies geographic restrictions. |
prl:industry | Specifies restrictions on the industry in which the resource may be reused. |
prl:usage | Specifies ways that the resource may be reused. |
The PRL Processing Model
Sets of declarations in PRL can be treated as RDF statements (see next section) and evaluated to determine if a resource can be used in a particular way. Conditions such as prl:industry and prl:greography and also prism:expirationTime and prism:releaseTime elements can evaluate to boolean values. Usage may be one of a set of controlled vocabulary terms that evaluate to the URI references #none, #use, #not applicable, and #permissionsUnkown. In PRL, expressions must appear only within the scope of a dc:rights element, or an rdf:Bag element if there are multiple statements. See PRISM 1.2 for further details of the processing logic.
