results from the Sherpa project led to their implementation in several
which have been applied to various domains.
Elsa has been developed jointly with CEMAGREF-Grenoble on top of
CEMAGREF is responsible for protection against snow avalanche hazard
(snow avalanches can destroy buildings, roads, ski resort devices and kill
people). The Elsa system is dedicated to support specialists in their
avalanche path analysis representing the mountain terrain and simulating
meteorological scenarii in order to evaluate the avalanche hazard.
The raw terrain is acquired through contour lines, ridges, thalwegs and
vegetation areas. It is represented by Shirka objects and presented to
the user through a graphic map. Then the user can build a spatial analysis
of the path in "panels". A small panel is a connex site area which is
homogeneous according to slope and vegetation and is not crossed by a
thalweg nor a ridge. It is also of reasonable size. This is the unit which
is taken into account in the specialist analysis process. These panels are
also represented in Shirka.
The user can then build or select meteorological scenarii which are plausible
for the area. These scenarii are simulated on the path. The simulation includes
the four phenomena involved in avalanche formation in the starting zone: snow
fall, snow drift, fracture, rupture propagation and flowing. Snow fall
determines the average snow precipitation on the path; snow drift leads to
the accumulation of snow on particular panels depending of the wind orientation
and strength; a fracture appears on a particular panel (called trigger) whose
snow cover is too unsteady; rupture propagation determines the panels released
by the trigger panel. This both quantitative and qualitative simulation provides
then the mass and velocity of the avalanche on the flowing zone.
Shirka does not only support the basic storage device for the path and scenarii
representation, it also offers inference mechanisms for automatically computing
various parameters such as snow height on a panel, rupture limit for a panel,
panel average elevation, the amount of snow... It thus constitutes the basic layer
of Elsa qualitative simulation. It also provide a reasoning maintenance (TMS)
facility which stores the computation results and ensures their validity.
Said is an application of Scarp, developed jointly with the IFREMER institute.
It is a knowledge based system for vibration analysis applying signal processing
techniques. It is used in order to support the diagnosis of vibrating structures,
such as offshore structures. This kind of diagnosis is complex and necessitates
frequent user intervention into the problem solving process: the input
parameters of the methods used are delicate to estimate, a trial and error
process is necessary, relying on the user interpretation of graphic
ColiGene is a knowledge base developed with
Shirka, designed jointly with a
research laboratory of the Lyon university (laboratoire de Biométrie,
et Biologie des Populations). It describes the regulation mechanisms within
the genome of Escherichia coli. The related knowledge is on one hand formalized
via the definition of object classes, such as gene, protein etc. Textual
definitions of these objects or other information concerning the regulation
mechanisms are on the other hand integrated via an associated hypertext network.
This allows to integrate free text or pictures, taken for example out of the
literature, into the knowledge base.
The firstfly base is the outcome of a common project between
and INRIA Rhône-Alpes
funded by an "Action coordonnée concertée:
sciences du vivant (13: informatique et génome)" of the french
ministry of education and research (MENESR).
The Firstfly knowledge base has been developped by Christophe Chemla under the
and the advices of Jérôme Euzenat.
Genetic expression does not only consist in translation and
transcription of genes into proteins because the presence or
lack of particular proteins can enable or disable the traduction.
These proteins, in turn, are produced by other genes. This
phenomenon (named interaction) has been studied for long in the
context of D. melanogaster.
The firstfly knowledge base is devoted to the reprensentation
of genetic interaction in the D. Melanogaster during its
early embryo development (it is restricted to the syncytial
blastoderm and cellular blastoderm development stages on the
It contains the description of the genes, proteins, interactions
that have been observed. . The base also refers to the notions
of expression context and network of interaction. It is already
possible to navigate through the network or to get the set of
possible paths from on product to another. The project is also
The knowledge base is browsable and usable through the WWW, but
it has not been released yet for public consultation.
- Simulate the action of interactions in a particular context
(e.g. a particular cell of a particular individual at a particular
- Retrieved the observations unexplained by the set of
interactions currently known;
- Display the interaction graphs
More information: Christophe Chemla, Une approche bio-informatique des
réseaux d'interactions géniques impliqués dans le
développement embryonnaire de Drosophila melanogaster,
DEA de biologie, Universit é de la méditéranée,
Marseille (FR), 1996
Mis-à-jour le 27/01/95