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Glossary of Terms
This glossary defines selected terms unique to the DOI® System, and other terms with
meanings used in a specific way within the DOI System. Refer to relevant sections of the
handbook for more information. Italicised terms are cross-references to other entries.
© International DOI Foundation 2006.
Actionable:
Of identifiers (1,2,3): implying that in the context of a particular piece of digital network
infrastructure, the identifier can be readily used to perform some action: e.g. in an
Internet Web browser, it can be "clicked on" and some action takes place.
Application Programming Interface (API):
A technical tool used in managing DOI names in relation to underlying technologies. A
description of functionality in a modular conceptual layer above the technology that
provides the functionality; in the case of the DOI System the API provides specifications for using the
Handle System® but avoids the need for users to address the Handle System directly and in
depth. The API ensures the portability of any code written to address DOI System services and
applications.
Base Application Profile (Base-AP):
A special case of an Application Profile in which the metadata set is identical to the kernel.
Creations:
Entities which are products of human imagination and/or endeavour in which intellectual
property rights exist; resources made by human beings, rather than other types of
resource (natural objects, people, places, events, etc). These may be manifested as Digital Objects, Physical Packages, Spatio-temporal Performances, or
Abstract Works. They correspond to intellectual property as defined by the World
Intellectual Property Organisation: "creations of the mind: inventions, literary and artistic
works, and symbols, names, images, and designs used in commerce". The initial focus of
DOI System applications is Creations; other types of resource are identified by DOI names only if
involved in intellectual property transactions (or in internal DOI System administration), and may
be identified by DOI names where appropriate.
Context:
The circumstances in which an act occurs, encompassing the entities of time, place, agent
and resource. The context model is the basis of the indecs data model and ontology.
Digital Object:
A data structure whose principal components are digital material, or data, plus a unique
identifier for this material. Note that a DOI name may be an identifier of such objects; but a
DOI name is not solely an identifier of such objects as it may also identify other entities and
creations.
DOI® Application Profile:
A set of DOI® names that share some common characteristics. A DOI® Application Profile is a grouping mechanism for DOI® names; the functional specification of the application profile includes a set of metadata, comprising the kernel metadata and additional information applicable to that particular genre of object and functional requirements. Each DOI name is associated with one or more Application Profiles.
DOI® Application Profile Framework:
An approach to efficiently grouping DOI names and connecting those groups to available services, giving application developers a way to go from a given DOI name to a set of services specific to that DOI name. This approach has been codified in the form of an API and answers the fundamental question of 'given a DOI name, what can I do with it?' In the framework, DOI names are linked into Application Profiles. Any single DOI name can be a member of one or Application Profiles; each Application Profile can be linked into one or more Services; and each Service can be made available through one or more interfaces. This layered approach is required both for usability and data integrity. As we add procedures and structures for layering DOI System information over the Handle System® it becomes increasingly important to define those procedures and structures in a separate layer. The Handle System is still there and its functionality is what enables the DOI System layer, but understanding and using the system will require building and using abstractions such as APs and Services.
DOI® Data Model:
The DOI® Data Model defines the connections between all of the DOI System operational components, enabling DOI names to be created and used in a consistent fashion. It combines the DOI Application Profile Framework and the DOI® Metadata System and the interaction between the two. Both of these major components have their own models and procedures, including the Handle System and the indecs Data Dictionary, which have been brought together and harmonized to effect true interoperability across DOI names from different domains and used within different applications.
DOI® Metadata:
Specific metadata associated with a referent within the DOI System, based on a structured data model that enables the referent of the DOI name to be associated with arbitrarily precise metadata to support description and services.
DOI® Metadata System:
The metadata component of the DOI System. A set of three components for semantic definition that provide well-formed and interoperable metadata to support the use of DOI names: the Kernel Metadata Declaration; indecs Data Dictionary; and Resource Metadata Declaration. The specification is designed to maximise semantic interoperability with existing metadata element sets, and to work with the DOI Application Profile Framework.
DOI® name:
The string that specifies a unique object (the referent) within the DOI System. Names may consist of alphanumeric characters in a sequence prescribed by the DOI syntax. (Note: the terms 'identifier' and 'number' are sometimes but not always used in the same sense and are to be avoided where ambiguity might arise. The unqualified use of 'DOI' alone may also be ambiguous: the term should instead always be used in conjunction with a specific noun (DOI name, DOI System, etc.).
DOI® name record:
The set of data (resolution values and administrative data) held in the DOI System as
current state data associated with a specific DOI name and returned on resolution.
DOI® Registration Agencies (RA):
Bodies appointed by the ISO Registration Authority to provide allocation of DOI names prefixes, registering DOI names and providing the necessary infrastructure to allow registrants to declare and maintain metadata.
DOI® Resolution:
The process of submitting a DOI name to a network service and receiving in return one or more pieces of current information related to the identified object. e.g., a location (URL) of the object or metadata. This may involve one or more intermediate mapping operations. The resolution may or may not return an instance of the object. Multiple resolution is the simultaneous return as output of several pieces of current information related to the object, in defined data structures.
DOI® Resource Metadata Declaration (RMD):
Form of message designed specifically for the exchange of metadata between DOI registration agencies to support their service requirements. It is developed by two or more registration agencies in accordance with format and schema specifications established by the Registration Authority.
DOI® Syntax:
The rules for the form and sequence of characters comprising any DOI name, specifically the form and character of a prefix element, separator, and suffix element.
DOI® System:
The functional deployment of DOI names as the application of identifiers in computer sensible form through assignment, resolution, referent description, administration, etc. as prescribed by this standard.
Entity:
Something that is identified. In principle a DOI name can be used (like any other URI
implementation) to identify any entity. In practice the DOI System is a combination of
components (identification, resolution, metadata and policies) devised with the specific
primary aim of identifying any "intellectual property entity". The initial focus of DOI System
applications is Creations. However other types of resource are also necessarily involved in intellectual property transactions, and so may be identified by DOI names where appropriate.
First-class:
Of an entity: an object in itself, not some attribute of an object; an address is an attribute
of something, whereas the something itself is a first class object. A DOI name references an entity
as a first-class entity, not simply the place where the object is located (it may then resolve
to a location).
Global Handle Registry®:
A component of the Handle System. A unique local handle service which stores naming authority handles. A query to the Global Handle Registry reveals which local handle services store which handles.
Handle:
An identifier (1) within the Handle System. DOI names are a subset of handles, but not the only
one. The relationship Handles:Handle System is analogous to DOI names:DOI System. DOI names
are distinguished from other handles by additional features and functionality, specifically
metadata and policy forming the totality of the DOI System described in this Handbook.
Handle System®:
The resolution component of the DOI System. A general-purpose distributed information
system designed to provide an efficient, extensible, and secured global name service for
use on networks such as the Internet. The Handle System includes an open set of
protocols, a namespace, and a reference implementation of the protocols. The DOI
System is one implementation of the Handle System; hence a DOI name is a handle. The Handle System if made up of local handle services.
(1) An unambiguous string or "label" that references an entity (e.g. ISBN 0-19-853737-9).
(2) A numbering scheme: a formal standard, an industry convention, or an arbitrary internal system providing a consistent syntax for generating individual labels or identifiers (1) denoting and distinguishing separate members of a class of entities (e.g. ISBN, or DOI® Syntax NISO Z39.84).
(3) An infrastructure specification: a syntax by which any identifier (1) can be expressed in a form suitable for use with a specific infrastructure, without necessarily specifying a working mechanism (e.g. URI).
(4) A system for implementing labels (identifiers (1)) through a numbering scheme (identifiers (2)) in an infrastructure using a specification (identifiers (3)) and management policies (e.g., DOI System).
indecsTM:
Acronym of "interoperability of data in e-commerce systems". The set of principles and
tools forming a Framework deriving from the indecs project and subsequently developed
into the indecs Data Dictionary; the basis for the DOI System approach to metadata.
indecsTM Data Dictionary (iDD):
Part of the DOI Data Model. A structured ontology, developed from the indecs
Framework, containing all Terms used in DOI® AP Metadata Declarations, ONIX messages
and other schemes, and formal mappings of the relationships between them, based on
indecs.
indecsTM principles:
Principles specified by the indecs project:
- Unique identification: every entity needs to be uniquely identified within an identified namespace;
- Functional granularity: it should be possible to identify an entity when there is a reason to distinguish it;
- Designated authority: the author of metadata must be securely identified;
- Appropriate access: everyone requires access to the metadata on which they depend, and privacy and confidentiality for their own metadata from those who are not dependent on it.
- Metadata is a relationship that someone claims to exist between two entities.
International DOI Foundation (IDF):
The organization established to develop and manage the DOI System.
Interoperability:
Enabling information that originates in one context to be used in another in ways that are as highly automated as possible.
Kernel metadata:
A compulsory small standardised set of metadata elements for every DOI name; the kernel is
common to every associated Application Profile. Each Resource identified with a DOI name must
have a supporting Kernel Metadata Declaration.
As the initial focus of the DOI System is on Creations, the initial kernel has been devised for Creations Other types of resource are identified by DOI names only if involved in intellectual property transactions, or in internal DOI System administration for the identification and management of Application Profiles and Services. When DOI names are applied to such other entities, the appropriate kernel will be defined.
Kernel Metadata Declaration (KMD):
The declaration of the Kernel metadata. For every resource identified with a DOI name, the
metadata declaration mandatory for all DOI names with associated metadata (i.e. all but those in
the Zero-AP), with standardised semantics and a supporting XML schema.
Local handle service (LHS):
A component of the Handle System. A local handle service is made up of one or more sites, and a site is made up of one or more handle servers. Handle servers store handles. One local handle service is unique, the Global Handle Registry®. "Local" implies simply that the particular service may be physically or logically confined to storing some administratively convenient subset of handles, such as all DOI names. Local handle services may also be implemented by a Registration Agency for their DOI names, for convenience.
(1) a single item of metadata is a relationship that someone claims to exist between two entities, each of which may have an identifier (an unambiguous string denoting an entity) and must, in an automated environment; a piece of data comprising the two entities and the relationship between them.
(2) (plural) a set of these relationships (data) having one entity in common, and thus forming data about that entity.
Multiple resolution:
Resolution returning a specific output of several pieces of current information related to
the DOI name identified entity, specifically at least one URL plus defined data structures
representing Application Profile and Service information. Multiple resolution goes hand-in-hand
with managing the object and its available services through structured metadata.
Native resolver:
A resolver plug-in that extends a web browser's functionality so that it understands the handle protocol. It will recognize a DOI name in the form doi:10.123/456, and resolve it to a URL or other file type the browser recognizes. The user simply "clicks" on the DOI name (or types the DOI name into the address line in their browser) and the DOI name is resolved directly. A browser plug-in has significant advantages (performance, functionality, non-reliance on other capabilities) when compared with the use of the proxy and an unextended browser, the more common user interface to the DOI System today. The development of additional services which depend on utilizing the full multiple resolution potential of the DOI System will necessitate the user being able to manage DOI name resolution directly.
Ontology:
An explicit formal specification of how to represent the objects, concepts and other entities
that are assumed to exist in some area of interest and the relationships that hold among
them. The indecs framework produced such an ontology, which has been further
developed and forms the basis of the indecs Data Dictionary.
Persistence:
The consistent availability over time of useful information about a specified entity:
ultimately guaranteed by social infrastructure (through policy) and assisted by technology
such as managed metadata and indirection through resolution which allows reference to a
first class entity to be maintained in the face of legitimate, desirable, and unavoidable
changes in associated data such as organisation names, domain names, URLs, etc. DOI names resolve to information (metadata) about an identified object in a manner intended to persist over changes in location, ownership, description methods, and other changeable attributes. If the object ceases to be available, the DOI name at a minumum indicates a valid but now defunct identifier.
Policy:
Rules determined by the International DOI Foundation for the operation of the DOI System
in a consistent, predictable, and controlled manner to ensure longevity of the system as
infrastructure.
Primary URL:
The default URL value which is provided from a DOI name single resolution; and also provided as
one value in the case of DOI name multiple resolution and specifically denoted as such in the DOI name
record. The default URL may represent an instance of the identified entity, or some
relevant metadata.
Proxy server:
A gateway between the Handle System and HTTP which enables resolution of a DOI name in the URL http:// syntax (e.g. doi:10.123/456 would be resolved from the address: http://dx.doi.org/10.123/456). Any standard browser encountering a DOI name in this form will be able to resolve it without the need to extend the web browsers capability, unlike the use of a native resolver. The use of the proxy server and an unextended browser provides the more common user interface to the DOI System today. The core DOI name resolution service is used by the proxy but is not constrained by the proxy. DOI names used through a HTTP proxy server (in the "http://dx.doi.org" formulation as a URL) will continue to be persistent.
Registrant:
An organization that registers DOI names through a DOI® Registration Agency.
Resolution:
The process in which an identifier is the input (a request) to a network service to receive in
return a specific output of one or more pieces of current information (state data) related to
the identified entity: e.g. a location (such as URL) where the object can be found.
Resolution provides a level of managed indirection between an identifier and the output.
In the case of the DOI System, the Handle System® technology provides the capability of
DOI name resolution. In the DOI System resolution is from a DOI name to one or more pieces of
typed data: e.g., URLs representing instances of the object, or services, or one or more
items of metadata.
Conceptually two cases are distinguished which are of significance in the DOI System: single resolution and multiple resolution.
Restricted Application Profiles (Restricted-AP):
Special cases of an Application Profile in which the metadata set is not available to all
users.
Service:
A defined result from a defined action i.e., do X and the result will be Y. DOI System services
perform specific functions when presented with data from DOI Application Profiles. This
may involve specific servers on the network or abstract notions such as a defined method
for comparing dates in documents with dates in DOI name records. "DOI System Service" is used in the
same generic sense as Web Services and the Grid Service architecture, but is not
restricted to either of those models. Like Application Profiles, Services are managed
separately, as classes; DOI names, APs and Services have many-to-many relationships.
Single resolution:
Resolution returning a specific output of one piece of current information related to the
DOI name identified entity, specifically a URL. The basis of early applications of the DOI System,
and of persistent identification through naming.
State data:
The current values of the data held in the DOI name resolution service in association with a
particular DOI name, returned in response to a resolution request.
Uniform Resource Identifier (URI):
An identifier (3) specification "any resource" on the Internet. A DOI name is a URI, and hence
the DOI System forms an identifier (4) system which implements the URI specification.
Well-formed:
Metadata elements and schemes which adhere to the indecs principles and so can be
understood outside a particular metadata scheme.
Z39.84:
The formal specification of the syntax for creating the DOI name string (identifier (2)),
"ANSI/NISO Z39.84-2000 Syntax for the Digital Object Identifier"
Zero Application Profile (Zero-AP):
A special case of an Application Profile in which the metadata set is empty. Only limited
functionality is possible with DOI names registered in the Zero-AP.
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