1.2 Semantic Interoperability
3
consists in defining the precise meaning of concepts. But it is not a time for academic
rigour.
As understood by the present work—necessarily in disagreement with others—
there are three aspects of interoperability, corresponding to the major branches of
theoretical linguistics: syntax, semantics and pragmatics. Syntactic interoperability is based on a common agreement on the grammar of a formal language, such
as a file format or the arrangement of data items in a stream or in memory, while
semantic interoperability refers to an agreement on the meaning or implications of
the communicated content. In the context of digitalization and the design of digital
infrastructures, the focus is typically on establishing a shared formalization of the
semantics (rather than syntax) for a particular application area, i.e. a domain of knowledge. Semantic interoperability can only be achieved if there are metadata standards
by which the annotation of data is carried out and understood by all participants in an
agreed way [16, 17]. This permits the integration of data communicated to a single
platform from multiple sources or by multiple users. This leads to interoperability
between multiple platforms whenever the developers of these platforms agree on
the same metadata standards or, where semantic heterogeneity remains, if an alignment can be constructed to harmonize the divergent standards [25–29]. Accordingly,
the meaning of concepts and relations needs to be agreed upon, while the technical
implementation and I/O are permitted to adhere to a variety of specifications and
formats.
Semantic metadata standards are also known as semantic assets; in Fig. 1.1, the
most common types of semantic assets are arranged by two main measures of their
expressivity and richness in content: First, the depth of the provided representation of
domain knowledge; second, the depth of digitalization, characterized by the extent to
which processing of the represented knowledge can be automated. At the minimum
with respect to both coordinates, only a list of concepts is compiled, i.e. a vocabulary
(or lexicon). If explanations and definitions are added in a way that is understandable
to human readers, this becomes a dictionary; in the field of materials modelling, this
includes the molecular model database (MolMod DB) nomenclature [4]. A hierarchy
of concepts is a taxonomy, where multiple narrower concepts are subsumed (symbol
) under a broader concept, yielding a tree structure, e.g. in the scientific taxonomy
of biological organisms
homo sapiens homo hominid primate mammal animal.
(1.1)
A thesaurus extends a system of concepts by definitions of possible relations between
individuals (objects) that instantiate them. For the use on digital platforms, this is
typically further formalized either as a hierarchical schema or as an ontology. In a
hierarchical notation (e.g. XML or JSON), relations take the form of containment,
e.g. in XML format, the tag representing one object can contain tags representing
subordinate objects, in an arrangement that is well defined by an XML Schema
Definition (XSD) and distinct from the taxonomic hierarchy of concepts. Applied to
the structure of a document, e.g. such a hierarchy might be given by
3
consists in defining the precise meaning of concepts. But it is not a time for academic
rigour.
As understood by the present work—necessarily in disagreement with others—
there are three aspects of interoperability, corresponding to the major branches of
theoretical linguistics: syntax, semantics and pragmatics. Syntactic interoperability is based on a common agreement on the grammar of a formal language, such
as a file format or the arrangement of data items in a stream or in memory, while
semantic interoperability refers to an agreement on the meaning or implications of
the communicated content. In the context of digitalization and the design of digital
infrastructures, the focus is typically on establishing a shared formalization of the
semantics (rather than syntax) for a particular application area, i.e. a domain of knowledge. Semantic interoperability can only be achieved if there are metadata standards
by which the annotation of data is carried out and understood by all participants in an
agreed way [16, 17]. This permits the integration of data communicated to a single
platform from multiple sources or by multiple users. This leads to interoperability
between multiple platforms whenever the developers of these platforms agree on
the same metadata standards or, where semantic heterogeneity remains, if an alignment can be constructed to harmonize the divergent standards [25–29]. Accordingly,
the meaning of concepts and relations needs to be agreed upon, while the technical
implementation and I/O are permitted to adhere to a variety of specifications and
formats.
Semantic metadata standards are also known as semantic assets; in Fig. 1.1, the
most common types of semantic assets are arranged by two main measures of their
expressivity and richness in content: First, the depth of the provided representation of
domain knowledge; second, the depth of digitalization, characterized by the extent to
which processing of the represented knowledge can be automated. At the minimum
with respect to both coordinates, only a list of concepts is compiled, i.e. a vocabulary
(or lexicon). If explanations and definitions are added in a way that is understandable
to human readers, this becomes a dictionary; in the field of materials modelling, this
includes the molecular model database (MolMod DB) nomenclature [4]. A hierarchy
of concepts is a taxonomy, where multiple narrower concepts are subsumed (symbol
) under a broader concept, yielding a tree structure, e.g. in the scientific taxonomy
of biological organisms
homo sapiens homo hominid primate mammal animal.
(1.1)
A thesaurus extends a system of concepts by definitions of possible relations between
individuals (objects) that instantiate them. For the use on digital platforms, this is
typically further formalized either as a hierarchical schema or as an ontology. In a
hierarchical notation (e.g. XML or JSON), relations take the form of containment,
e.g. in XML format, the tag representing one object can contain tags representing
subordinate objects, in an arrangement that is well defined by an XML Schema
Definition (XSD) and distinct from the taxonomic hierarchy of concepts. Applied to
the structure of a document, e.g. such a hierarchy might be given by