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Digital
Object Identifier
The Digital Object Identifier (DOI) was
developed and maintained by the International
DOI Foundation (IDF) to describe the digital objects
for "intellectual right management". The DOI
system is made up of four components including Enumeration,
Description, Resolution and Policies,
each of which depends on others for its value.
Enumeration is the way of DOI system
to construct unique identifiers. Each DOI is a unique
string assigned to identify one entity (resource). It
can be used to identify any of the various physical objects
that are "manifestations" of intellectual property;
or less tangible manifestations, such as the digital files;
or the performance of intellectual property and the "abstractions"
that underlie the different manifestations. The DOI can
be seen as a persistent identifier, which means
that even the ownership of the entity or the rights in
the entity has changed, the identification of that entity
should not (and does not) change. This is the core of
DOI system.
The DOI identifier has two components: prefix
and suffix. The prefix is assigned by DOI
Registration Agencies (currently are the CrossRef,
Content Directions,
Inc, Enpia
Systems, Ltd., and
Learning
Objects Network, Inc.) Actually the DOI is an implementation
of CNRI Handle system
that uses "10."
as the start of prefix followed by a number. The suffix
can be assigned uniquely by the organization that has
applied the prefix. It can be any alphanumeric string
but must be unique within that given prefix. Combining
prefix and suffix together can get a unique identifier
for one entity.
DOI system uses the Handle system developed
by Corporation
for National Research Initiatives (CNRI) to resolve
its identifier to the associated information in the network.
The Handle System is a comprehensive system for assigning,
managing, and resolving persistent identifiers, such as
DOI for digital objects and other resources on the Internet.
The Handle System includes a set of protocols,
a namespace (prefix and suffix), and an implementation
of the protocols. The protocols enable a distributed computer
system such as Internet to store handles of digital resources
(e.g. DOI) and resolve them into the information necessary
to locate and access the resources. This function is very
similar to the Domain Name Services (DNS) for resolving
the IP address.
Although one entity can be uniquely identified
by its DOI identifier, this string only can be manipulated
by computer and normal user could not get real meaning
from it. It's necessary to combine metadata with the identifier
together to provide a meaningful method for user describing,
searching and accessing the entity. Metadata is an essential
component of the DOI System.
The DOI system also defines a very small
but mandatory Metadata elements set, which only includes
six elements: Identifier, Title,
Mode, Type, Primary
Agent, and Agent Role. Since there
is a variety of intellectual property types exist that
requires different Metadata elements sets to describe
them, DOI system needs to expand the scope of Metadata
elements to describe them. It adopts INDECS
Metadata Framework as its Metadata model because INDECS
schema is also designed for the same domain - intellectual
property.
The INDECS (Interoperability of Data in
E-Commerce Systems) project was established in1998, and
ended in March 2000, which was evaluated as successful
by the project Commission. It aimed to develop specific
metadata for electronic commerce that enables the interoperability
of different metadata for different media and functions
in electronic trade activities. The key point is how to
unambiguous identify and describe the rights of using
intellectual property, which could not be provided by
other Metadata schema such as Dublin Core. It focuses
on the "creation, modification, use and 'publishing'
of entities, and the conditions to enable these events:
transactions, agreements, offers and payments".
INDECS defines the attributes of the entities,
the roles they contain, relations, parties, creations,
Intellectual Property, IPR (Intellectual Property Rights)
Transactions, Assertions and Non-textual Metadata. The
INDECS framework contains a Metadata model, and a high-level
Metadata dictionary, principles for mappings to other
schemas, and a Directory of Parties proposal. Although
the project has been closed, the INDECS partners established
a non-profit organization called INDECS
Framework Ltd. that continues maintaining and developing
the INDECS Framework.
For specific type of entities, the Metadata
elements set would be quite different from another set
in DOI system. To clearly define the structure of that
elements set and its registry, a DOI
Application Profile (DOI-AP) is defined as part of
the Metadata.
DOI-AP is initially defined in terms of
a class of Intellectual Property entities and an application
(or set of applications). The purpose of a DOI-AP is to
enable the implementation of application (or set of applications)
in a particular environment. Those applications can range
from relatively simple resource discovery to complex e-commerce
and rights management applications. Besides the definition
of the metadata schema, DOI-AP also contains the commercial
and procedural rules (which can include, for example,
rules relating to the exploitation of the metadata that
is declared), the Registration Agency or Agencies responsible
for its application, and DOI User Community responsible
for its management.
To learn more about Digital Object Identifier,
please check The
DOI Handbook from International DOI Foundation (IDF).
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