Research fields cover a wide disciplinary spectrum from
thermodynamics to cognition, encompassing fluid mechanics, energetics,
acoustic and voice synthesis, spoken language and text processing,
vision, visualisation and perception, virtual and augmented reality.
They cover five main scientific domains :
A large part of LIMSI research
potential is devoted to developing man-machine communication and
interaction systems. Part of these systems are based on automatic
analysis of both written and spoken language, covering all aspects from
signal processing to semantics. Processing
of written language concentrates more specifically on information
mining from large bodies of heterogeneous documents through the
development of question-answer systems. Processing
of spoken language deals with automatic transcription of spoken
dialogues on various supports, and aims at the identification of
locutors, language recognition and identification of emotions. A recent
development concerns speech to speech automatic translation with
statistical methods. In addition, gesture analysis, related to deaf
language, opens news paradigms for man-machine communication.
The previous domain results and reciprocally begs for the
development of advanced interfaces, combining and blending modalities,
for a natural, adaptive, smart interaction. Research in
this direction concerns the study, integration and evaluation, in
computer systems, of all different possible means of interaction, non
only between a man and a machine but also between groups of people
through distributed collective networks. Part of these developments
begs for advances in fundamental questions on human perception, both
visual and audible, in relation with its associated cognitive
Research in virtual
reality at LIMSI is principally oriented towards the additional
dimension brought by immersion in the development of new forms and
concepts of man-machin interaction. It focuses on multi-modality
both in its visual, audio and haptics components. Part of this
activity is dedicated at developing augmented reality concepts in
relation with medical and artistic applications. Advantage is also
taken of the in-house virtual reality facilty to develop
applications for immersive CAO through industrial collaborations.
Another main objective is the interactive visualization of the huge
sets produced by the modelisation and simulation of large physical
systems, like in bio-informatics or fluid mechanics.
Activities in this field are aimed at comprehending the mechanisms of instability which may take place
in the transition from laminar flow states to turbulence, as well as
improving the prediction of turbulent flows, in particular of large scale unstationnary structures.
These objectives require continuous methodological improvements for the numerical integration of the
flow equations, concerning modelling and approximation but also comparison to turbulent achievements.
These breakthroughs are used for the treatment and the control of several external and internal flows.
In this field, most of research aims at a better understanding,
modelling and ultimately mastering of the heat and mass transfer that
takes place between a solid and a fluid. For one part, studies of the
elementary or isolated phenomena , such as boiling on a single site or
homogenization of periodic porous media, are performed in order to
derive their macroscopic properties and hence optimize the systems in
which they intervene. In general, the complexity of the situations at
hand favor principally experimental investigations, like in micro-scale
configurations or kinetics of adsortion where the quality of metrology
is essential. In addition, modeling and numerical simulation are
developed, like in the growth of isolated vapor bubbles or for the
thermodynamical analysis of natural convection in cavities. In
parallel, a good deal of efforts go into developing thermoacoustics,
both from a technological and scientific standpoint. The technological
finality, whose objective is the conception of thermal machines for
producing cold at cryogenic temperatures, requires putting together
scientific skills, such as in velocity measurements through PIV,
thermohydraulic instabilities, conjugate heat transfer in oscillating
non-Boussinesq convection or even homogeneization.