Achieved as part of an Esprit II project, the main purpose of this thesis was the realisation of a knowledge based system for network design. lbrough the development of this system called NEST (for Network design Expert SysTem), two mains research axes have been undertaken : the modelling of a design activity for which the artificial intelligence has relatively weak theories and the local area network design for which few experts systems have been coll).puted. The originality of the used approach is to have made use of se veral formalisms : object centred models for the basic concepts, prolog to implement operative knowledge and an architecture composed of control plans 1 tasks 1 sub-tasks 1 modules. Furthermore, to implement a knowledge based system, it is necessary to represent domain knowledge. Sorne particular points have been emphasised such as object oriented programming and design methods used in knowledge based system. The development of NEST is part of MMI2 project whose main objective is to realize a multi-modal interface for knowledge based systems. The various modes allowed by this interface are the naturallanguages (english, french, spanish), the graphies, the gesture and a command language. A first demonstrator has been presented in October 91 and during the Esprit conference in November 1991 in Bruxelles.
