Knowledge bases as Web page backbones
INRIA Rhône-Alpes, 655 avenue de l'Europe, 38330 Montbonnot Saint-Martin (France)
Knowledge bases and hypermedia
The mixing of knowledge bases and hypermedia has been already achieved for
long (see Gaines, 1990,
Rechenmann, 1993). Such an idea can be put forth for various reasons:
project, at INRIA Rhône-Alpes,
Grenoble, designs tools and models for knowledge representation. This
work blends together four kinds of knowledge through corresponding
representation units: object-based representation;
task models; behavioural equations; hypertext and lexicon.
- The knowledge out of knowledge bases cannot be seen in isolation
from other knowledge sources available in the firms or
laboratories: bibliographic references, full text papers,
experimental data and programs. This relationship must be established
in one way or another. For anyone who wants to explain, to
annotate or at least to document a knowledge base, "hypermedia" are
now the main support;
- The success of the World-Wide Web enables the publication of
a knowledge base.
Thus even users with little computer knowledge can have access to it
at low cost: one server can have many users on cheap workstations;
- Another, deeper, reason is the conviction of several researchers
that one major interest of a knowledge base is the possibility to
consult it as an encyclopaedia. This idea is related to the
knowledge medium concept (Stefik, 1986).
It has been further investigated by
(Gaines, 1990) and
was already able to link formal knowledge with pictures and texts
through a proprietary hypermedia system.
A knowledge base on E. coli
genome has been built with it
We are currently developing a new system
(with its HTTP server counterpart HyTropes)
and are involved in the craft of a knowledge base on the fruit fly (D. melanogaster) genome.
Here are described the advantages of the Web as a hypermedia management
system related to a knowledge base, but above all the advantages of
generating Web pages from a knowledge base instead of generating them
by hand or from documents.
The knowledge hypermedium
As already noted by various authors (see
LINKS database, WebMap)
an object-based representation system is already a web of related objects.
Thus, the similarity between Web pages and objects is quite obvious and the
mapping from one to another is straightforward. The WWW mode of browsing
is thus a natural interface to object systems.
Knowledge bases can be used as Web servers whose skeleton is the
structure of formal knowledge (mainly in the object-based formalism)
and whose flesh consists of pieces of texts and images tied to the
objects. Turning a knowledge base system into a Web server is easily
achieved by connecting it to a port and transforming each object
reference into an URL. If the knowledge base is already documented by
Web pages, the latter remain linked to or integrated into the pages
corresponding to these objects.
The advantages of such an approach with regard to the previous proprietary
hypertext systems are chiefly the availability of the knowledge base
content to a wide and untrained audience. HyTropes participates in the
knowledge medium idea promoted by Mark Stefik. However, other advantages
are found in the consistency of the base (there is no dangling link since
the skeleton is generated automatically and formal information is supposed
to be sound).
Intelligence added web servers
World-wide availability and safety are precious contributions, however
they are quite restricted with regard to the possibilities of knowledge
As a matter of fact, from a knowledge base server it is possible to
build complex queries grounded on the formal knowledge (see figure).
For instance, a user looking for an apartment in a real estate knowledge
base can first select a filter form from the "house" concept, ask the
lexicon for the meaning of the slot/word "F3" and decide to fill
the form with corresponding criteria; the user can select one of the
objects given as answers and have a look at the ground map and at a
picture of the house together with the usual precise information.
This combines the advantages of a very structured server with the
freedom of usual servers. Moreover, the answer will be given in
function of a semantically grounded method instead of using a simple
HyTropes makes filtering queries
available and we are currently implementing the classification aspect
(the mechanism is simpler but this requires more work on displaying
classification results on trees; see
technicalities below). In fact the whole
is subject to URLising. So the next step will consist in publishing
the URL rules (far simpler than the URL generated by the
FORM tag) in order to enable any other application to:
The queries can be as complex as required: it will be possible not
only to browse but also to build and modify knowledge bases. This raises
problems of concurrent access and user support. Thus, since 1995, we have
been working on the
construction of knowledge bases for expressing the consensus between a
community of geographically distributed people. Each researcher has a
knowledge base from which knowledge can be isolated and submitted to the
consensual knowledge base. The latter base will then contact the other
members of the group for acceptation, rejection or comments on the submitted
piece of knowledge. This requires formal comparison and merging
of contributions from several knowledge sources and a robust
protocol for such a task. A complete protocol has been designed for
these activities and the research about knowledge base comparison is ongoing.
- properly query a knowledge base;
- generate Web pages linked with any knowledge base.
For long some people have been thinking that knowledge bases are
interesting as formal repositories of knowledge rather than
as problem solvers. Knowledge-based Web pages can be read as
hypermedia documents and also interrogated for problem solving
(Gaines and Shaw, 1992). The success of the world-wide web is an
opportunity to test this idea in the large.
The Web is an ideal support for the diffusion of knowledge, but we
pretend that the formal representation of knowledge is a very important
issue for the Web. As a matter of fact, the answers actually provided
by the various Web worms are so huge and so often irrelevant that formal
organisation of knowledge will soon be unavoidable. This should
help the user and the server to share some content (as required by
The technical aspects of the available Tropes server are presented in the
HyTropes home page together with
a simple demonstration
of the program and the
The missing items of classical knowledge base browsers are the graph display
of hierarchical data (e.g. class trees or graphs). An
of Thomas Koch's
written in Java is used in order to display our own class hierarchies. More development on colour and behaviour of
the nodes is required.
Related but non linked references
(Gaines , 1990)
Knowledge based systems 3(4):192-203, 1990
(Perrière& , 1993)
Guy Perrière, Christian Gautier,
ColiGene: object-centered representation for the study of E. coli
gene expressivity by sequence analysis,
Biochimie 75(5):415-422, 1993
(Stefik , 1986)
The next knowledge medium,
AI magazine 7(1):34-46, 1986