The Concept Coding Framework an application of the Semantic Web
Andy Judson, Nick Hine
Division of Applied Computing, University of Dundee, Dundee, Scotland
Mats Lundälv
DART, Regional habilitering, The Queen Silvia Children’s Hospital, Kruthusgatan 17, Göteborg, Sweden
Bengt Farre
RigAB/Androtech, Göteborg, Sweden
Keywords: Internet Computing, Accessibility Issues and Technology, Semantic Web, Personalized Web Sites and
Abstract: The World Wide Web offers many services from typical textual web content to shopping, banking and
educational services, for example, virtual learning environments. These technologies are inherently complex
to use, but in their very nature offer many benefits to the disabled person. The traversal of the web relies
upon the cognitive skills of the user. You need to know what you want to do. You need to understand what
the site is allowing you to do, and you need to be able to complete the task by interacting with the website.
The emergence of the semantic web offers the potential to reduce the cognitive burden of understanding
what the site can do and how to complete a task, whilst also offering new solutions to typical accessibility
issues. In this paper, we aim to present how the semantic web can be used to enhance accessibility. Firstly
we’ll give some examples of what is currently possible. Secondly we’ll motivate some research initiatives to
enhance user independence for the disabled person, particularly those that use Augmentative and
Alternative Communication (AAC) systems and/or are Learning Impaired.
The World Wide Web offers many services from
typical textual web content to shopping, banking and
educational services, for example, virtual learning
environments. These technologies are inherently
complex to use, especially when navigated through
alternative devices (Huang & Sundaresan, 2000;
Sloan, et al, 2000), but in their very nature offer
many benefits to the disabled person.
Disabled users of the web are more common
an many might believe with one in three families
in the world touched by disability (Theofanos &
Redish, 2003). Their article, Bridging the Gap
continues to make some critical points, i. the number
of people with disabilities and disposable incomes is
likely to increase; ii. users with disabilities spend
more time logged on than non-disabled users; and
iii. the internet opens up many barriers and provides
enhanced independence freedom for people with
The internet is currently a web of links, the
ersal of which relies upon the cognitive skills of
the user. That is, they need to know what they want
to do, they need to understand what the site is
allowing them to do, and they need to be able to
complete the task by interacting with the website.
The current focus of web accessibility is that of
e interaction problem, i.e. the navigation of a site.
The emergence of the semantic web offers the
potential to reduce the cognitive burden of what the
site can do and how to complete a task, whilst also
offering new solutions to typical accessibility issues.
Judson A., Hine N., Lundälv M. and Farre B. (2005).
EMPOWERING DISABLED USERS THROUGH THE SEMANTIC WEB - The Concept Coding Framework an application of the Semantic Web.
In Proceedings of the First International Conference on Web Information Systems and Technologies, pages 162-167
DOI: 10.5220/0001227801620167
The semantic web is a framework for data to be
reused across different applications and boundaries.
It is an extension of the current web that provides
machine-readable information whose meaning is
well-defined by standard protocols. (Berners-Lee,
2003). Much of the semantic web research and
development is focused on either the business
opportunities, on knowledge management, or test
environments to explore ideas and tools, for
instance, “Friend of a Friend” (FOAF). Little so far
has been explored that focuses on the end the user,
particularly the disabled user. In this paper, we aim
to present how the semantic web can be used to
enhance accessibility, firstly with what is currently
possible, and secondly to motivate the research to
enhance user independence for the disabled person,
particularly those that use Augmentative and
Alternative Communication (AAC) systems and/or
are Learning Impaired.
Augmentative and Alternative Communication
(AAC) users are persons with a speech impairment
that is a result of a congenital (eg. Cerebral Palsy) or
acquired dysfunction (eg. Multiple Sclerosis, or
Aphasia following a stroke). People with these kinds
of disabilities have a range of impairments that are
usually a combination of sensory, physical,
cognitive and speech problems. (Edwards, 1995).
A typical task that adults do, for example,
organising travel can be very complicated for a
disabled person. They need to know about physical
access to the hotel, disability friendly amenities and
the flight arrangements will need to accommodate
their special needs. Could the semantic web make
the burden of arranging this trip much simpler? We
could envisage a time when the disabled user should
be able to tell a search engine, “I want to attend the
ISAAC conference in Brazil” (International
Conference of 2004 on Augmentative and
Alternative Communication). The user’s agent /
browser would then return options ready to purchase
with the flights, hotel arrangements, and all special
requirements already filtered based on a user profile
that, for example, takes into account their physical
or dietary needs. The architecture of the semantic
web is intended to do just that. The user’s agent will
be able to ask intelligent questions of a website. The
solution will be provided from the rules and the
ontologies that the website uses, and these can
bridge different domains, all interoperating
seamlessly. This is currently a vision of the future,
an anticipated result of the emergence of the
semantic web. For now though, we can exploit the
semantic web with applications of it in constrained
domains to address access issues previously
The AAC user needs a communication aid to
interact with others in everyday situations. These
systems may be populated with a variety of
symbolic representations of language concepts
(abstract entities / meanings). For instance, the
sequence of concepts, “I, belly, yesterday, (to) hurt”
could be interpreted as “I had a sore belly
yesterday”. This form of communication is common
for symbol users and each of the concepts could be
represented as a symbol on the users’ device as
shown in Figure 1, where four different symbol sets,
Bliss, PCS, Pictogram and Beta are used (in rows,
top-to-bottom) to show how they would each portray
the same message.
Figure 1: “I had a sore belly yesterday”,
represented in Bliss, PCS, Pictogram and Beta.
Referencing to and exchanging between
proprietary, symbols
encoded messages, becomes
problematic in Internet environments. For example,
if Andy constructs a message using his English PCS
symbol vocabulary and sends it via email to his
friend Mats, a person who uses Bliss and lives in
Sweden, then Mats may wish to read the message in
Swedish Bliss representation, that is his personal
graphic symbol and language preference. Such
translation on a concept-by-concept basis presents a
number of problems for the user. For instances
Mats’ replacement symbol language, Bliss may not
include equivalent representations of the PCS
concepts used by Andy, or may have two or more
representations of the same concept. These
difficulties are caused by a lack of common
practices in the definition of concepts for graphic
symbol systems in general, and concept encoding
EMPOWERING DISABLED USERS THROUGH: The Concept Coding Framework an application of the Semantic Web
schemes in particular. The development of a
Concept Coding Framework (CCF) intends to
change that.
The CCF is designed as an application of the
Semantic Web. It will offer AAC users enhanced
accessibility of the Internet and will remove barriers
for message exchange. The Semantic Web as a
whole potentially offers these same users more
support and independence. This all sounds great in
theory, but developing such solutions is very
complicated, and will be a rather long-term
commitment. This is clear from the rate of progress
with the Semantic Web itself. Development started
with Tim Berners-Lee’s road map in 1998, by
February 2001 we had an Activity Statement from
the World Wide Web Consortium (W3C) Semantic
Web Initiative and in February 2004 we saw the
Resource Description Format (RDF) and Web
Ontology Language (OWL), (the backbone to the
Semantic Web) become standard technologies of the
Users of AAC systems experience significant
difficulties when interacting in the text-rich Internet
environment. Web accessibility experts feel Internet
users with learning difficulties present an especially
complex challenge (Seeman, 2002; Clark, 2003).
The existing Web Content Accessibility Guidelines
(WCAG) from the W3C, WCAG 1.0 clearly focus
on the visual impaired users, but the emerging
guidelines, WCAG 2.0 are certainly taking more
notice of the other groups of users, as more groups
of accessibility experts focus or specialise, for
instance, in Learning Difficulties (LDWeb). Existing
solutions or recommended techniques say amongst
other things, “use plain language”, but even this idea
is vague and how this could be achieved is still
debated in many accessibility forums and discussion
threads. With the emergence of new technologies as
part of the Semantic Web Initiative we now have the
capabilities and potential to start to address the
issues of web accessibility for persons with learning
difficulties (Seeman, 2004). With time, we should
see user agents that can fulfil the vision of simpler
travel as outlined above.
Jakob Nielsen’s Alertbox article “Alternative
Interfaces for Accessibility” (Nielsen, 2003)
describes the conflict between practical and ideals
when implementing a perfectly usable design.
Neilsen states that the practical solution chosen
through cost and maintenance is to provide a “single
design for multiple audiences”; where as the ideal is
to provide “separate designs optimized for each of
main access modalities”. This ideal is achievable
through the technique of separating content from
presentation; hence the prolific development of
Cascading Style Sheets (CSS), whose power in
terms of accessibility is driving many online
accessibility communities to deliver beautiful and
highly accessible content.
The Concept Coding Framework is a new
potential solution that is being specifically
developed to provide a mechanism for repurposing
content into preferred symbolic representations
through the use of semantic web technologies for the
AAC user. This is an opensource and international
initiative that resulted from the pan-European
WWAAC project, which aimed to enhance access to
the World Wide Web for the AAC user through
various routes (Lundälv, et al, 2003; Poulson &
Nicolle, 2003; Magnuson & Hunnicutt, 2003).
Concept coding offers an extra level of
separation - that of the actual meaning of the content
from its representation. So in addition to the text in
the HTML paragraphs, RDF annotations are
provided that map the words in the text to their
generic concepts. It is then the responsibility of the
user-agent, for example, the user’s web browser, to
parse the annotations and thus repurpose (on the fly)
the textual content into their preferred language, and
if necessary symbolic representation. Lisa Seeman
of UB-Access is also investigating the use of the
Semantic Web to repurpose material into an
accessible form suitable to users via a system known
as the Semantic Web Accessibility Platform
(SWAP). SWAP uses a proxy server to translate
content into a form that suits the users’ profile,
however, it does not look at the AAC user.
3.1 Concept Coding Framework
Many AAC systems use some kind of graphical
symbols to represent a limited vocabulary of basic
concepts. However, there is a lack of widely
accepted standards for the language, concept,
symbol, and encoding schemes of these
vocabularies. This then means that translation
between the different vocabularies and text is
The CCF provides a foundation for, and a bridge
between, current and future proprietary AAC
systems, by supporting effective graphic symbol
usage, exchange and maintenance in the context of
standard Internet information sharing. To be
acceptable as mechanism for exchanging messages,
concept codes should be:
Clearly defined, harmonising where possible,
with the emerging principles for general
concept management in the Internet.
Non-Proprietary and publicly accessible.
Exchangeable over the web.
Culture and language independent.
Simple and straightforward to implement.
Provide clear benefits for end-users.
As with any other language, symbol sets are
dynamic entities, families and professional carers
supporting AAC users are likely to need or want to
understand the technical complexities of such a
system. Therefore, there is a requirement for
mechanisms to support the framework, such as, a
facility for the addition of new concepts, and the
maintenance of the ontologies (a database of terms
used to describe and represent an area of knowledge,
in this case language.
To achieve this, the proposed CCF must rely on
a stable foundation of concepts with unique IDs
referring to one or more Reference Ontologies where
the concepts are clearly defined – including their
relations to other concepts. It is strategically
essential that there is a rich and thoroughly defined
natural language ontology at the root of this
The Base Reference Ontology (BRO) contains
around 4000 - 12000 concepts that are a subset of
WordNet, an electronic lexical reference system
(Fellbaum, 1999), supported by a small
Complementary Reference Ontology (CRO) of
about 200 - 1000 common function words and
specialized concepts not covered by WordNet.
Figure 2 illustrates the structure of the proposed
framework. The CCF is built up of 3 parts connected
by a Bridge. These are:
Figure 2: Concept Coding Framework
Structure Overview
2. The Concept Code Definitions (CCD) acts as a
controlled vocabulary of concepts currently
supported by the CCF. Each concept is defined
by its own unique ID, and through references
into the Reference Ontologies.
3. The Base Reference Ontology (BRO), which
contains the concepts and their definitions,
including relevant parts of the hierarchy,
relations and some linguistic information. This
resource is currently derived from WordNet,
but alternative or complementary ontologies
may potentially be utilised.
4. The Complementary Reference Ontology
(CRO), which contains the concepts currently
not found in WordNet (primarily around 200
common function words, such as pronouns,
prepositions, and question words). These
concepts are grouped in simple hierarchies,
with other relational and linguistic information
corresponding to that of the BRO.
Each proprietary ontology owner who wants
their users to benefit from the CCF will have to take
on the responsibility to create a mapping between
the concepts in their own ontology and the concept
codes in the CCD, the entry point into the
framework. The APIs and a CCF Template Bridge
are being developed as part of the Framework to
support the mapping process.
An alternative view of CCF is a nerve spine,
with each proprietary system tapping in & out of it
(See Figure 3).
Figure 3: Concept Coding Framework
Spine Visualisation
The large column on the left is the CCF. The
CCD is the nerve stem running down the spine to the
BRO coupled with CRO that form the base of the
column. Vendors (e.g. Widgit and Handicom) then
create a mapping from their respective Assistive
Ontology onto the CCD. These Assistive Ontologies
are then linked into the CCF, allowing requests to be
routed between them (e.g. between Widgit and
Handicom concepts).
EMPOWERING DISABLED USERS THROUGH: The Concept Coding Framework an application of the Semantic Web
In a similar manner different natural language
lexicons, providing additional text representations,
may be related as Assistive Ontologies. Note: The
English one is already present as part of the
3.2 Concept Coded Documents
We will not define a new document format or
specify one to use as that would go against all
principles of the web and steer us into proprietary
formats. Instead, we suggest the use of RDF (W3C,
RDF) coupled with other technologies, namely
OWL (W3C, OWL), XPointer (W3C, XPointer) and
Ruby Annotation (W3C, Ruby Annotation) as a
means to provide concept coding to existing
document formats. For example, imagine a very
simple webpage that just contains the text “I want a
cup of coffee”. One way, and probably the tidiest for
adding concept codes, is to link in a mapping file of
the concept codes and representation references
from the document header.
The linked, RDF/XML file contains the concept
code references for the text in the html, after some
initial declarations of namespaces, each word or
phrase would be mapped by an XPointer to its
concept code in the CCD, and possibly some
alternative representations, for instance Bliss, as
shown in the following “coffee” RDF example
The Standard Bridge is then used to map this
definition to entries in the BRO and/or the CRO.
Then, for instance, the Reference Ontology would
contain an entry that has a text representation of the
concept and possibly refers back to the original
WordNet ontology. In this example there would also
be a Bliss extension of the Bridge that maps the
concept code to a code in the Bliss Assistive
Everyday tasks such as shopping for groceries may
be a complex and tiring rigmarole for the disabled
person. Online shopping may provide many benefits
to this user group, but using these services is still
very complex and hard work. This Christmas, online
spending was expected to include 43% of consumers
in the UK (BBC News, 2004). There is a move from
the high street to eRetailers. There is also a move of
shoppers from eRetailers with the cheapest product
to eRetailers with better service, websites and
customer reviews. Indicating that some customers,
according to individual preferences and
prerequisites, in some instances are beginning to
prefer shopping online to traditional shopping. It
also indicates the need for eRetailers to improve the
accessibility to their services – for customers in
general and for disabled users in particular.
The Aurora (Huang & Sundaresan, 2000) system
was a proxy facility to address the issues of
comprehension and navigation as faced when using,
for example, an auction site like eBay. However,
their system was developed pre Semantic Web. They
relied upon manually made custom profiles of sites
to allow each facility to be successfully re-purposed.
The Semantic Web can potentially reduce
barriers of understanding and provide enhanced user
independence. But this is still a long way off, and
poses “the grand challenge for the current generation
of computer technology” (Embley, 2004).
<link rel="ConceptCoding" href="mapping.ccf">
The CCF will form the basis of a number of new
research and opensource development initiatives that
will take concept coding to another level of
sophistication and flexibility. A demonstrator exists
that allows you to explore a test framework, which
includes a facility for composing simple messages
that can translate to different symbol sets.
Eight million disabled European citizens with
language disability (about 20% of the current total
disabled population) are not, or are in only a very
limited manner able to make use of the possibilities
that modern information technology provides. The
challenge of the WWAAC project has been to make
the Internet more accessible, thereby increasing the
quality of life for this target group of users.
With the help of European Community funding
it has been possible to start to develop an open
source standard. The CCF can through
standardisation enable users to be more active
members of the society. The CCF when matured will
assist their education, independence, and
The developments of the Concept Coding
Framework show that it is possible to create a
common bridge between various graphic symbol
systems and textual languages. This is definitely a
step in the right direction as a solution to providing
understandable content. The CCF can bridge
between different technologies and products
developed for AAC users and also between Assistive
Technologies (AT) and the mainstream technologies
of today. In the future, assistive devices employing
CCF technologies will be able to exploit the
Semantic Web in numerous ways. For instance, their
user agents could roam the web on a mission to
perform sophisticated tasks, like a organising a trip,
for them in an automated manner.
Future work of the CCF Interest Group is
focused on the delivery of tools and plug-ins for the
development and support of the framework.
Particularly, the objective is to develop and evaluate
a full-scale vocabulary (CCD), supported by a large-
scale repository of ontologies (BRO, CRO and
Assistive Ontologies). It is vital that this work is
performed in co-operation with key vendors and
stakeholders of the field.
We are grateful to the contributing members of the
Concept Coding Interest Group, particularly Charles
McCathieNevile and Lisa Seeman; also David Sloan
and Saqib Ashraf for their advice and comments in
the writing of this paper.
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EMPOWERING DISABLED USERS THROUGH: The Concept Coding Framework an application of the Semantic Web