Evolving hypermedia middleware services

Abstract

KEYWORDSOpen hypermedia system (OHS), component-based open hypermedia system (CB-OHS), hypermedia middleware, distributed system services, distributed system architectures ABSTRACT In this paper, we consider the evolution of hypermedia system architectmes from the monolithic systems of the 198(ys to the middleware-oriented component-based open systems of today. We look at the various problems that users and system designers encountered with systems at various stages of this development, focusing particularly on problems that were solved or caused by moving toward a more middleware-oriented approach. Although we cast our discussion in tetms of specific hypermedia systems, we believe that many of our observations on the advantages and challenges of our current middleware approach may be helpful to those in other areas of system research.

Supporting virtual documents in just-in-time hypermedia systems

“…Separating links from content means that the links can be managed in a more sophisticated manner, but within OHS research there has also been an emphasis on supporting external applications [9], and dealing with structures beyond the traditional navigational link [19], including virtual documents].…”

Relationships among structural computing and other fields

“…Currently, the generic structural abstraction, or 'structural atom', in both Callimachus and Construct (Wiil and Nürnberg, 1999) is a highly generic abstraction with 'built-in' structuring capabilities. That is, these atoms are able to be related to one another.…”

“…This objection seems reasonable, at least inasmuch as openness at this level is in fact not stressed in structural computing work (although it clearly is a part of existing structural computing systems, such as Callimachus or Construct (Wiil and Nürnberg, 1999). Indeed, in , Construct is used to illustrate the multiple open services concept.)…”

Addressing interoperability in open hypermedia: the design of the open hypermedia protocol

“…Construct is a CB-OHS under development at Aarhus and Aalborg Universities in Denmark (47). This work builds on previous open hypermedia services research conducted over the last decade (e.g., HOSS (4), HyperDisco (5), and DHM (48)).…”

“…The set of interfaces developed and standardized so far addresses presentation interoperability, i.e., it focuses on interoperability between content handlers and domain specific middleware components (47). The main benefits of this approach lie in allowing different clients to interoperate with different middleware servers.…”