Difference between revisions of "Basic Concepts"

Revision as of 14:41, 29 November 2007

Virtual Research Environments and Community Portals

Communities of scientists and research use the gCube middleware and Grid resources to setup Virtual Research Environments (VRE) for Content exchange and collaboration. The gCube empowered VRE provides a framework of applications, services and resources to support the underlying processes of research. The purpose of a VRE is to help researchers in all disciplines by managing the increasingly complex range of tasks involved in carrying out research.

Portals provide the required tools for content search, browsing, annotation, metadata management and other value added capabilities.

Content and Collections

The Content concept encompasses the data and information that the VRE handles and makes available to its users. It is composed of a set of information objects organized in collections. Content is an umbrella concept used to aggregate all forms of information objects that a VRE collects, manages, and delivers. It encompasses the diverse range of information objects, including such resources as objects, annotations, and metadata. For example, metadata have a central role in the handling and use of information objects, as they provide information critical to its syntactical, semantic, and contextual interpretation.

Communities exploit any VRE collection through the features offered by the Web Portals.

Content Annotation

As a definition of annotation we could say that it is a written explanation or criticism or illustration that is added to a document. Informally, annotations are comments or notes made by users in order to expose their ideas about a document. The annotations’ role in a digital library is very important since they promote collaboration between the users of the library. Through annotations, new ideas and concepts can be discussed something which may help the understanding of an annotated object and the advance of knowledge about it.

In gCube a number of different types of annotations are provided. The first distinction has to do with the content of the annotation. So, there are text annotations and associations. By adding a text annotation a user may add a comment or a note about a gCube resource. On the other hand, associations are used in order to create conceptual links between two or more resources. Moreover, annotations can be applied to the whole document or just to a part of it. In the first occasion text annotations or associations are denoted as generic or non-anchored annotations and in the second as anchored.

Generic annotations should be used when the comment or the association is referred to the whole entity. General comments, notes and additional information about a document belong to that category. Non-anchored annotations introduce a more interesting concept of annotating an object. Now, the author is able to bring in information about a specific part/ fragment of the resource. Presumably, this extends the capabilities of a user as he may indicate in a visual and descriptive way the part of the document where his comment refers to.

Metadata

The “classic” definition of metadata is “data about data”. Metadata are used for describing different aspects of data, such as the semantics, provenance, constraints, parameters, content, quality, condition, and other characteristic. These data can be used in different contexts and for a diversity of purposes; usually, they are associated with an Information Object as a means for facilitating the effective discovery, retrieval, use and management of the object. There are a number of schemes for classifying metadata. One of them consists in classifying metadata according to the specific role they play:

Descriptive metadata, i.e. metadata that provide a mechanism for representing attributes describing and identifying the Resource. Examples include bibliographical attributes (e.g. creator, title, publisher, date), format, list of keywords characterising the contents. The term “descriptive” is used here in a consistent, but broader sense than in “descriptive cataloguing”. 

Administrative metadata, i.e. metadata for managing a Resource. This category of metadata may include metadata detailing: (i) technical characteristics of the Resource, (ii) the history of the operations performed on the Resource since its creation/ingest, (iii) means of access, (iv) how the authenticity and integrity of the Resource can be verified.

Preservation metadata, i.e. metadata designed to support the long term accessibility of a Resource by providing information about its content, technical attributes, dependencies, management, designated community(ies) and change history. Preservation Metadata have been identified as essential for the long-term management of digital objects. The Reference Model for an Open Archival Information System (OAIS) provides an excellent overview of the role of preservation metadata in the management overtime of digital resources.