Polythematic Structured Subject Heading System
Encyclopedia
Polythematic Structured Subject Heading System (abbreviated as PSH from the Czech
Polytematický Strukturovaný Heslář) is a bilingual Czech-English controlled vocabulary
of subject headings developed and maintained by the National Technical Library (the former State Technical Library) in Prague
. It was designed for describing and searching information resources according to their subject. PSH contains more than 13,500 terms, which cover the main fields of human knowledge. Thanks to its releasing in SKOS, PSH can be used not only for describing documents
in a library
, but also for indexing web pages
. Everyone can use PSH for free. PSH is a part of the Linking Open Data cloud diagram (LOD cloud diagaram). The image of the LOD cloud diagram shows datasets that have been published in Linked Data
format, by contributors to the Linking Open Data community project and other individuals and organisations.
The vast majority of new subject headings is suggested and approved by the indexing experts from the National Technical Library. However, the users and public can also make suggestions, using an online form, which are then assessed by the experts. The main decisions about the development and the future of PSH are done by the Committee for Coordination of Polythematic Structured Subject Heading System. The Committee consists of specialists from the National Technical Library and cooperating institutions, and representatives from the libraries and companies which use PSH. The Committee meets once a year in the National Technical Library; in the meantime, the members communicate using an electronic mailing list
.
with 44 thematic sections. Subject headings are included in a hierarchy of six (or seven) levels according to their semantic
content and specificity. There are hierarchical
, associative ("see also") and equivalence
("see") relations in PSH. Hierarchical relations are represented by broader and narrower terms (e.g. physical diagnostic methods is broader term to electrocardiography, and on the other hand, electrocardiography is narrower term to physical diagnostic methods). Equivalence relations link subject headings with their nonpreferred versions (e.g. electrocardiography and ECG). Moreover, associative relations are used to link related subject headings from different parts of PSH, regardless their affiliation to a section, (e.g. electrocardiography: see also cardiology). Every subject heading belongs to just one section, which has its own two-character abbreviation, assigned to every subject heading of the section. This enables users to recognize affiliation of subject headings from lower levels to the thematic sections. The 44 thematic sections have following root nodes
:
, which is implemented in library automated systems
. PSH is also available in SKOS, using RDF/XML
syntax, which is a version suitable for web distribution. Single headings can be accessed on the PSH website through URI
links. Alternatively, the whole vocabulary can be downloaded in one file. It is possible to display tags from PSH (metadata
snippets - Dublin Core
and CommonTag), which can be embedded in an HTML document to provide its semantic description in a machine-readable way.
Czech language
Czech is a West Slavic language with about 12 million native speakers; it is the majority language in the Czech Republic and spoken by Czechs worldwide. The language was known as Bohemian in English until the late 19th century...
Polytematický Strukturovaný Heslář) is a bilingual Czech-English controlled vocabulary
Controlled vocabulary
Controlled vocabularies provide a way to organize knowledge for subsequent retrieval. They are used in subject indexing schemes, subject headings, thesauri, taxonomies and other form of knowledge organization systems...
of subject headings developed and maintained by the National Technical Library (the former State Technical Library) in Prague
Prague
Prague is the capital and largest city of the Czech Republic. Situated in the north-west of the country on the Vltava river, the city is home to about 1.3 million people, while its metropolitan area is estimated to have a population of over 2.3 million...
. It was designed for describing and searching information resources according to their subject. PSH contains more than 13,500 terms, which cover the main fields of human knowledge. Thanks to its releasing in SKOS, PSH can be used not only for describing documents
Document
The term document has multiple meanings in ordinary language and in scholarship. WordNet 3.1. lists four meanings :* document, written document, papers...
in a library
Library
In a traditional sense, a library is a large collection of books, and can refer to the place in which the collection is housed. Today, the term can refer to any collection, including digital sources, resources, and services...
, but also for indexing web pages
Web indexing
Web indexing includes back-of-book-style indexes to individual websites or an intranet, and the creation of keyword metadata to provide a more useful vocabulary for Internet or onsite search engines...
. Everyone can use PSH for free. PSH is a part of the Linking Open Data cloud diagram (LOD cloud diagaram). The image of the LOD cloud diagram shows datasets that have been published in Linked Data
Linked Data
In computing, linked data describes a method of publishing structured data so that it can be interlinked and become more useful. It builds upon standard Web technologies such as HTTP and URIs, but rather than using them to serve web pages for human readers, it extends them to share information in a...
format, by contributors to the Linking Open Data community project and other individuals and organisations.
History and development
The PSH preparation project started in 1993, supported by several grants from the Czech Ministry of Culture and Czech Ministry of Education, Youth and Sport. Since 1995, PSH has been used for indexing the State Technical Library’s documents. Starting 1997, PSH has been distributed to other libraries and companies, originally as a commercial, paid product; since 2009 for free. In 2000, the State Technical Library received a grant from the Ministry of Culture to translate PSH into English. The next milestone in its development was its releasing in the SKOS format, in 2009.The vast majority of new subject headings is suggested and approved by the indexing experts from the National Technical Library. However, the users and public can also make suggestions, using an online form, which are then assessed by the experts. The main decisions about the development and the future of PSH are done by the Committee for Coordination of Polythematic Structured Subject Heading System. The Committee consists of specialists from the National Technical Library and cooperating institutions, and representatives from the libraries and companies which use PSH. The Committee meets once a year in the National Technical Library; in the meantime, the members communicate using an electronic mailing list
Electronic mailing list
An electronic mailing list is a special usage of email that allows for widespread distribution of information to many Internet users. It is similar to a traditional mailing list — a list of names and addresses — as might be kept by an organization for sending publications to...
.
PSH structure
PSH is a tree structureTree structure
A tree structure is a way of representing the hierarchical nature of a structure in a graphical form. It is named a "tree structure" because the classic representation resembles a tree, even though the chart is generally upside down compared to an actual tree, with the "root" at the top and the...
with 44 thematic sections. Subject headings are included in a hierarchy of six (or seven) levels according to their semantic
Semantics
Semantics is the study of meaning. It focuses on the relation between signifiers, such as words, phrases, signs and symbols, and what they stand for, their denotata....
content and specificity. There are hierarchical
Hierarchy
A hierarchy is an arrangement of items in which the items are represented as being "above," "below," or "at the same level as" one another...
, associative ("see also") and equivalence
Equivalence relation
In mathematics, an equivalence relation is a relation that, loosely speaking, partitions a set so that every element of the set is a member of one and only one cell of the partition. Two elements of the set are considered equivalent if and only if they are elements of the same cell...
("see") relations in PSH. Hierarchical relations are represented by broader and narrower terms (e.g. physical diagnostic methods is broader term to electrocardiography, and on the other hand, electrocardiography is narrower term to physical diagnostic methods). Equivalence relations link subject headings with their nonpreferred versions (e.g. electrocardiography and ECG). Moreover, associative relations are used to link related subject headings from different parts of PSH, regardless their affiliation to a section, (e.g. electrocardiography: see also cardiology). Every subject heading belongs to just one section, which has its own two-character abbreviation, assigned to every subject heading of the section. This enables users to recognize affiliation of subject headings from lower levels to the thematic sections. The 44 thematic sections have following root nodes
Tree (data structure)
In computer science, a tree is a widely-used data structure that emulates a hierarchical tree structure with a set of linked nodes.Mathematically, it is an ordered directed tree, more specifically an arborescence: an acyclic connected graph where each node has zero or more children nodes and at...
:
- agriculture
- anthropology
- architecture and town planning
- art
- astronomy
- biology
- chemistry
- civil engineering
- communications
- computer technology
- consumer industry
- economic sciences
- electronics
- electrotechnics
- food industry
- generalities
- geography
- geology
- geophysics
- health services
- history
- informatics
- information science
- law
- linguistics
- literature
- mathematics
- mechanical engineering
- metallurgy
- military affairs
- mining engineering
- pedagogy
- philosophy
- physics
- politology
- power engineering
- psychology
- religion
- science and technology
- sociology
- sport
- theory of systems
- transport
- water management
PSH formats
The main format for storage, maintenance and sharing PSH is the MARC 21 Format for Authority DataMARC standards
MARC, MAchine-Readable Cataloging, is a data format and set of related standards used by libraries to encode and share information about books and other material they collect...
, which is implemented in library automated systems
Integrated library system
An integrated library system , also known as a library management system ,is an enterprise resource planning system for a library, used to track items owned, orders made, bills paid, and patrons who have borrowed....
. PSH is also available in SKOS, using RDF/XML
RDF/XML
RDF/XML is a syntax, defined by the W3C, to express an RDF graph as an XML document. According to the W3C, "RDF/XML is the normative syntax for writing RDF"....
syntax, which is a version suitable for web distribution. Single headings can be accessed on the PSH website through URI
Uniform Resource Identifier
In computing, a uniform resource identifier is a string of characters used to identify a name or a resource on the Internet. Such identification enables interaction with representations of the resource over a network using specific protocols...
links. Alternatively, the whole vocabulary can be downloaded in one file. It is possible to display tags from PSH (metadata
Metadata
The term metadata is an ambiguous term which is used for two fundamentally different concepts . Although the expression "data about data" is often used, it does not apply to both in the same way. Structural metadata, the design and specification of data structures, cannot be about data, because at...
snippets - Dublin Core
Dublin Core
The Dublin Core metadata terms are a set of vocabulary terms which can be used to describe resources for the purposes of discovery. The terms can be used to describe a full range of web resources: video, images, web pages etc and physical resources such as books and objects like artworks...
and CommonTag), which can be embedded in an HTML document to provide its semantic description in a machine-readable way.
See also
- ThesaurusThesaurusA thesaurus is a reference work that lists words grouped together according to similarity of meaning , in contrast to a dictionary, which contains definitions and pronunciations...
- Library of Congress Subject HeadingsLibrary of Congress Subject HeadingsThe Library of Congress Subject Headings comprise a thesaurus of subject headings, maintained by the United States Library of Congress, for use in bibliographic records...
- Information retrievalInformation retrievalInformation retrieval is the area of study concerned with searching for documents, for information within documents, and for metadata about documents, as well as that of searching structured storage, relational databases, and the World Wide Web...
- Semantic WebSemantic WebThe Semantic Web is a collaborative movement led by the World Wide Web Consortium that promotes common formats for data on the World Wide Web. By encouraging the inclusion of semantic content in web pages, the Semantic Web aims at converting the current web of unstructured documents into a "web of...