Reusable System Architectures - Man-Machine Dialogue: Design and Challenges - page 70

direction between the models). The toolkit then generates models, and, after
one or more generation and deriving phases, ends up by generating code that
can be run. Today, these highly software-oriented approaches do not
sufficiently take into account the needs of the users and cannot be easily
adapted to processes that are as complex as those of automatic natural
language understanding. We have to admit that the definition of models and
metamodels is problematic, especially if we want to take into account the
specificities of natural language and natural dialogue, let alone multimodal
dialogue: a common representation language for all the models has to be
defined, so as to help the development environment manage them. Yet
acoustic, lexical, syntactic, semantic, pragmatic models, models describing
the structure of a dialogue, or even models for pointing gestures, involve a
huge variety of knowledge for which there are no interconnected
representation standards. Moreover, processes for speech recognition,
syntactic analysis, reference resolution, mental state attribution, etc. are also
the focus of representations in dedicated models. And if these descriptions
and formalisms exist, there is still an important effort to be made to achieve
usable representations in the case of a model-driven approach.
4.2.2. Middleware for man-machine interaction
An alternative, which may join the OpenDial challenges described at the
end of the Chapter 1, is in the design of middleware adapted to the MMD's
need. Middleware is an interconnection software component that consists of a
set of services allowing multiple processes to run on one or more machines
and interact through a network. Closer to our concerns, middleware is also,
and above all, a software component that becomes a conversion and
translation layer between two processes. Originally, middleware was
essentially a system middleware, that is a conversion layer inserted between a
flow of data generated by a specific machine and the machine's operating
system. We then distinguish explicit middleware (proxy layers between the
operating system and any application run on it) and implicit middleware
(mediation or interpretation process between a business application and
the matching presentation application). The field of MMI has led to the
development of various pieces of implicit middleware. Lard et al. [LAR 07]
offer an implicit middleware based on a multilayer architecture to promote
the development of man-machine interaction systems by including a few very
simplified MMD aspects. The principle resides in adding a layer devoted to