Tuesday, November 21, 2006

A Case study on 5S

5S, a fundamental abstraction of digital libraries, stands for Streams, Structures, Spaces, Scenarios and Societies. 5S proposes a formal language and model to describe digital libraries.

The advantage of using a formal language and model, according to its creators (Goncalves, et al. ), is that they are precise and unambiguous when defining semantics of specific abstractions of a knowledge field. Thus, 5S could be used as an instrument for
1) building and interpretation of a DL taxonomy,
2) informal and formal analysis of case studies of digital libraries and utilisation as a formal bases for a DL description language.
Moreover, 5S could be used for requirements analysis in Digital Library development.

An example of a case study to describe a digital library using the main elements of 5S is presented below, taking Learning Resources Exchange as an example.

5S, a fundamental abstraction of digital libraries, stands for Streams, Structures, Spaces, Scenarios and Societies. Streams are sequences of arbitrary items used to describe both static and dynamic content. Structures impose organisation. Spaces are stets with operations on those sets that obey certain constraints. Scenarios consist of sequences of events that modify states of a computation in order too accomplish a functional requirement. Societies are sets of entities and activities and relationships among them. The below case study illustrates of what each “S” is comprised of.

  • primary community: European teachers and learners
  • repository providers: public authorities who make the decision about joining
  • repository maintenance and running, editorial control
  • some pedagogical support, etc.
  • commercial providers

Scenarios (services, different corresponding scenarios)
  • trainings to help authorities to hook up to the federation
  • training to help teachers to use the system and submit material to it and creating the metadata
  • scenarios to maintain the service and content?
  • Scenarios on how to access the site, through browsing and searching, in one or federation (SQI)

  • physical location of members (a metric space)
  • vocabularies and metadata used in different services (conceptual space). In addition to this, also manual, semi-automatic, and automatic indexing and classification methods to relate repositories to the conceptual space of ELR.
  • User interfaces (APIs?) to relate various software routines (like LMS etc)

  • simplest level they are streams of characters for text, and streams for pixels for images; audio, digital files. Challenges for quality of system if in real-tine or storage problems at the local level if downloaded and locally played
  • Network protocols, transmissions of serialised streams over the network such as federated search, harvesting, hybrid services using protocols like Dienst, Z39.50, OAI-PMH,...

  • database management system at the heart of the software for submission and workflow management.
  • Xml to store and exchange the resources' metadata
  • EUN Application profile
  • structures in the form of semantic networks, any?

S5 as a description language.

The paper, using S5 Descriptive Language, defines a digital library as follows:

A digital library is a 4-tuple (R, DM, Serv, Soc), where
  • R is a repository;
  • DM= {DM c1, DM c2, ...DM ck} is a set of metadata catalogs for all collections {C1, C2,...Ck}
  • Serv is a set of services containing at least services for indexing, searching and browsing;
  • Soc is a society.

“ We should stress that the above definition only captures the syntax of a digital library, that is, what a digital library is. Many semantic constraints and consistency rules regarding the relationships among the DL components (e.g. How the scenarios in Serv should be built from R and DM and from the relationships among communities inside the society Soc, or what the consistency rules are moment digital objects in collections of R and metadata records in DM) are not specified here. Those will be a subject of future research. “

Tuple: in a database, an ordered set of data constituting a record; a data structure consisting of comma-separated values passed to a program or operating system.

GONCALVES, M., A., FOX E., A,, WATSON, L., T. and KIPP, N.,A. (200 ).
Streams, Structures, Spaces, Scenarios, Societies (5S): A Formal Model for Digital Libraries
Virginia Polytechnic Institute and State University

No comments: