<kwd>
Keyword
A keyword is a finding aid used to record one subject term, key phrase, abbreviation, indexing word, taxonomic structure, or other expression that is associated with a whole structure (such as an article). Keywords can be used for identification, searching, and indexing purposes. A keyword element (<kwd>) may contain a repetition of words found in the structure, or it may contain broader terms, narrower terms, related terms, or taxonomic identifiers used to find the structure in a search or provide semantic classification of the text by mapping a specific structure to a taxonomy.
Remarks
Key words are contained in <kwd-group>s. There may be several <kwd-group>s, each of which can be identified separately by language, vocabulary, or taxonomy source. None of the individual keyword elements (<kwd>, <compound-kwd>, <nested-kwd>) take the @xml:lang attribute; that is reserved for the <kwd-group>. This means that keywords must be sorted by language and entered in language groups.
Related Resource: For a discussion on the use of <kwd>, see Keywords.
Best Practice: In this Tag Set, nested keywords (<nested-kwd>) should be reserved for hierarchical material such as taxonomies. There are a few journal/book tag sets in which keyword nesting is used to simulate a two-part list. Such a keyword list should be tagged as a <def-list> instead.
Attribute Best Practice: If the content of the <kwd> element is a term from a controlled vocabulary (ontology, taxonomy, term-list, vocabulary, industry glossary, or other known source), the vocabulary attributes should be used to identify that source. The source named can be a formal ontology or an informal field of study.
Term Identification Attributes: Two attributes are used in this Tag Set to identify an individual term from a vocabulary (controlled or an uncontrolled):
vocab-term | The content of the element is the display version of the vocabulary or taxonomic term. The @vocab-term attribute holds the canonical version of the same term, as it appears in the vocabulary. For example, if the attribute value is “digitized-vor”, the element might contain the display text “Digitized Version of Record”. |
|---|---|
vocab-term-identifier | Unique identifier of the term within a specific vocabulary, such as (but not limited to) an item number, a URI, DOI, etc. |
Vocabulary Identification Attributes: Two attributes are used in this Tag Set to identify a vocabulary. If these attributes have already been used on <kwd-group>, they need not be repeated on each <kwd>.
vocab | Name of the controlled or uncontrolled vocabulary, taxonomy, ontology, index, database, or similar that is the source of the term. For example, for a subject term, a value might be the IPC Codes (“ipc”) or MESH headings
(“mesh”). For an uncontrolled term, the value might be
an area of study such as “medical-devices” or merely the word “uncontrolled”. |
|---|---|
vocab-identifier | Unique identifier of the vocabulary, such as (but not limited to) a URI or DOI. For example, for Dublin Core (DCC), the identifier may be “http://dublincore.org/documents/2012/06/14/dces/”. |
Attributes
Content Model
<!ELEMENT kwd (#PCDATA %kwd-elements;)* >
Expanded Content Model
(#PCDATA | bold | fixed-case | italic | monospace | overline | roman | sans-serif | sc | strike | underline | ruby | named-content | styled-content | sub | sup)*
Description
Any combination of:
- Text, numbers, or special characters
- Emphasis Elements
- <named-content> Named Special (Subject) Content
- <styled-content> Styled Special (Subject) Content
- Baseline Change Elements
This element may be contained in:
Example 1
An author’s list of keywords for a document:
... <article-meta> ... <abstract>...</abstract> <kwd-group kwd-group-type="author"> <kwd>DNA analysis</kwd> <kwd>gene expression</kwd> <kwd>parallel cloning</kwd> <kwd>fluid microarray</kwd> </kwd-group> </article-meta> ...
Example 2
Multiple keyword groups for a document, where each group was created by a separate organization or process:
... <article-meta> ... <kwd-group kwd-group-type="Inspec"> <kwd>diversity reception</kwd> <kwd>Doppler radar</kwd> <kwd>Doppler shift</kwd> <kwd>encoding</kwd> <kwd>optimisation</kwd> <kwd>orthogonal codes</kwd> <kwd>radar signal processing</kwd> <kwd>MIMO radar</kwd> </kwd-group> <kwd-group kwd-group-type="uncontrolled"> <kwd>polyphase codes optimisation</kwd> <kwd>multiinput-multioutput radars</kwd> <kwd>radar performance</kwd> <kwd>diversity technique</kwd> <kwd>MIMO radar transmission</kwd> <kwd>diversity performance</kwd> <kwd>orthogonal codes</kwd> <kwd>Doppler sensitive</kwd> <kwd>side-lobes level</kwd> <kwd>adaptive clonal selection algorithm</kwd> <kwd>polyphase coded orthogonal signals</kwd> <kwd>aperiodic autocorrelation side lobe</kwd> <kwd>Doppler shift tolerance</kwd> <kwd>sustainable Doppler shifts</kwd> <kwd>Doppler tolerance performances</kwd> </kwd-group> <kwd-group kwd-group-type="Inspec-class"> <compound-kwd> <compound-kwd-part content-type="code">B0260</compound-kwd-part> <compound-kwd-part content-type="text">Optimisation techniques</compound-kwd-part> </compound-kwd> <compound-kwd> <compound-kwd-part content-type="code">B6140</compound-kwd-part> <compound-kwd-part content-type="text">Signal processing and detection</compound-kwd-part> </compound-kwd> <compound-kwd> <compound-kwd-part content-type="code">B6320</compound-kwd-part> <compound-kwd-part content-type="text">Radar equipment, systems and applications</compound-kwd-part> </compound-kwd> </kwd-group> </article-meta> ...
Example 3
Multiple keyword groups for a document (including Japanese):
... <article-meta> ... <kwd-group xml:lang="en"> <kwd>heated air</kwd> </kwd-group> <kwd-group xml:lang="ja"> <kwd>加温空気</kwd> </kwd-group> ... </article-meta> ...
Example 4
Nested keyword in section metadata to provide navigation information for an app:
...
<sec>
<sec-meta>
<kwd-group specific-use="mobile-nav">
<nested-kwd>
<kwd>dosing</kwd>
<nested-kwd>
<kwd>geriatric</kwd>
<nested-kwd>
<kwd>Digoxin</kwd>
</nested-kwd>
</nested-kwd>
</nested-kwd>
</kwd-group>
<kwd-group specific-use="mobile-nav">
<nested-kwd>
<kwd>Digoxin</kwd>
<nested-kwd>
<kwd>dosing</kwd>
<nested-kwd>
<kwd>geriatric</kwd>
</nested-kwd>
</nested-kwd>
</nested-kwd>
</kwd-group>
</sec-meta>
<title>Dosing Table, Geriatric</title>
...
</sec>
...
Example 5
Keywords with vocabulary and vocabulary-term identifiers:
...
<kwd-group kwd-group-type="physh" xml:lang="en"
vocab="PhySH" vocab-identifier="https://physh.org/">
<nested-kwd>
<kwd content-type="facet"
vocab="PhySH" vocab-identifier="https://physh.org/"
vocab-term-identifier=
"https://physh.aps.org/browse?facetIds=Research%2520Areas"
>Research Areas</kwd>
<nested-kwd>
<kwd content-type="concept"
vocab="PhySH" vocab-identifier="https://physh.org/"
vocab-term-identifier=
"https://doi.org/10.29172/ba7ccb8ed7eb4e6f9c1eb622f5b4e242"
>Atomic & molecular processes in external fields</kwd>
<nested-kwd>
<kwd content-type="concept"
vocab="PhySH" vocab-identifier="https://physh.org/"
vocab-term-identifier=
"https://doi.org/10.29172/da893accf204480b8a7e386479c50687"
>Coherent control</kwd>
</nested-kwd>
</nested-kwd>
</nested-kwd>
<nested-kwd>
<kwd content-type="facet"
vocab="PhySH" vocab-identifier="https://physh.org/"
vocab-term-identifier=
"https://physh.aps.org/browse?facetIds=Physical%2520Systems"
>Physical Systems</kwd>
<nested-kwd>
<kwd content-type="concept"
vocab="PhySH" vocab-identifier="https://physh.org/"
vocab-term-identifier=
"https://doi.org/10.29172/bd252d88a60848979416daf84dee7f6b"
>Atomic Systems</kwd>
<nested-kwd>
<kwd content-type="concept"
vocab="PhySH" vocab-identifier="https://physh.org/"
vocab-term-identifier=
"https://doi.org/10.29172/42e66168abfd4328aa9df6fc3a077f75"
>Molecules</kwd>
</nested-kwd>
</nested-kwd>
</nested-kwd>
</kwd-group>
...