A Personalisable Electronic Book for Video-based Sign Language ...

Personalising Hypermedia Presentations
Figure 6. A Test in KSO
In KSO, the requests a user can issue to personalise hypermedia presentations are based on the annotating and
rewriting of hyperpage specifications. An annotation pairs a hyperpage specification with notes of interest.
These notes assign user-specific values to user-generic attributes of interest (e.g., The level of difficulty is high,
the presentation medium is video, etc.). The existence of annotations allows for the personalisation of a
specified chunk, a hyperpage, or a complete hypermedia presentation. Annotations are meta-data that describe
the content and/or behaviour of a hyperpage or its component parts.
In KSO, both hyperpages and their associated annotations are stored in the hyperlibrary. The hyperlibrary is
implemented as a database (using the PostGreSQL relational database management system), comprised of
relations over the relational schemas for hyperpages and hyperpage annotations. Further details on the
modelling of the hyperlibrary can be found in (Ohene-Djan J, 2000).
Personalisation Engine
We view personalisation as the process of handing over to the user the ability to take actions to tailor hyperpages
and, therefore, hypermedia presentations. The personalisation engine is initially set using a static user-model
(Fischer G, 2000), which is a representation of a user’s knowledge of sign language knowledge. This is initially
set, as a result of a student’s answers to a series of sign language exercises, when a user first registers with the
system. This user model provides the means for a user to feed preferences into the personalisation engine.
These details are then used to tailor which hypermedia content is made available for further personalisation by
the user.
Personalisation in KSO is implemented as a software mechanism that is responsible for providing the
functionality required to tailor hypermedia presentations. Such tailoring causes a personalised version of a
hypermedia presentation to be created. The dynamics of the personalisation mechanism may be understood as
follows. The personalisation process starts when a user issues a personalisation request, via a UIS, to KSO. A
personalisation request is comprised of a scope, which denotes the collection of hyperpages in the hyperlibrary
for which the request should apply, and an action list, containing the tailoring actions to be executed over the
scope. The interface used to issue such requests is shown in Figures 7 and 8. The example personalisation
request shown in Figure 7 may be represented in natural language as “I wish to be presented with all pages that
contain the string ‘1997’; subsequently delete the second chunk of each of these pages.” Figure 8 can be
represented as “I wish to be presented with all pages in the hyperlibrary. Of these pages, only keep those that
contain the string ‘1998’ in the second chunk.”
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