[ba-ohs-talk] FOHM--the Fundamental Open Hypertext Model
http://www.equator.ecs.soton.ac.uk/technology/linky/linky0.5/intro/fohm_desc
ription.html (one of dozens of pages <~1030> when you google FOHM) (01)
Excerpts:
"The Fundamental Open Hypertext Model (FOHM) [6] grew out of the Open
Hypermedia Protocol (OHP) developed by the Open Hypermedia Systems Working
Group (OHSWG) but it expands the OHP data model to describe a broader set
of hypermedia "domains". FOHM also makes no assumptions about the protocol
it is running over or the systems that are using it. It is a model for
describing hypertext structures that requires binding to a syntax before it
can be used" (02)
"In its work on interoperability, the OHSWG considered the requirements of
several domains of hypertext. The three most frequently mentioned were
Navigational, Spatial and Taxonomic Hypertext. The OHP protocol was always
more concerned with Navigational Hypertext, however FOHM is capable of
expressing all three domains. Before we can examine FOHM it is necessary to
define these domains.
Navigational Hypertext is the most traditional domain of hypertext,
exemplified in Open Hypermedia Systems such as Chimera[1], DHM[3],
HyperForm[11], Microcosm[2] and the HB/SP series[9]. Authors create Links
between parts of documents that are related. Users can then click on those
links to move between documents. Although Navigational Hypertext systems
can be quite sophisticated, by far the most popular system, the World Wide
Web, is also one of the simplest.
Spatial Hypertext systems allow users to organise their information
visually in a process known as "Information Triage"[5]. Relationships
between nodes are expressed by their visual characteristics such as
proximity, colour or shape. This results in visual collections, or Spaces,
such as lists and sets. Spatial hypertext systems are therefore ideal for
an evolving organisation of data. Examples of such systems include VIKI[4]
and CAOS[8].
Taxonomic Hypertext is the organisation of information artifacts into
Categories[7]. Where authors disagree about the categorisation, the
Taxonomy can branch into different Perspectives[10]. Applications can allow
users to navigate the information space by moving between overlapping
Categories and can also reason about the relationships that artifacts have
with one another. " (03)
"In FOHM we describe four first-class objects that are analogous to the
objects in the OHP data model. Associations are structures that represent
relationships between Data objects. These Data objects are wrappers for any
piece of data that lies outside of the scope of the model. They normally
represent a document although one could represent any file, stream or other
item. It is exactly this feature that we shall use to make links between
concepts and queries. Data objects are not directly placed in the
Associations. Instead Reference objects are used, these either point at
Data objects in their entirety or at parts of those Data objects, for
example the second paragraph of a text document, or the second scene of a
film. They are attached to the Association object via Bindings. Each
Association also has a structure type and a feature space; each Binding
must state its position in that feature space, effectively stating how it
is bound to the Association's structure. " (04)
"Where the FOHM model differs from other open hypermedia models is in its
placement of context at the heart of the information. Context is left as an
opaque object within the FOHM model with the specifics being defined by the
implementation.
Context objects can be attached to all parts of the FOHM structure ..." (05)
"In addition to context, behaviour objects can also be attached to the
different parts of the FOHM data structures. Like context objects,
behaviour objects are also opaque. Unlike context objects however the
implementation of the FOHM model is not required to understand the contents
of the behaviour object..." (06)
Originally, according to the Hypertext 2001 proceedings, there was an
implementation called "Auld Leaky." Now, it is known as "Auld Linky"
http://www.equator.ecs.soton.ac.uk/technology/linky/linky.shtml
complete with downloads (it's Perl, I don't yet know the license). (07)
What's particularly curious (for me) is the resemblance to topic maps. It
strikes me that their "contexts" are a topic map's "scopes", though topic
maps don't do "behaviors." FOHM appears to be association-centric, while
topic maps appear to be topic-centric. I'd really like to see what others
think about FOHM. (08)
Cheers!
Jack (09)