possible to know how these process models were generated, and they become dependent on the domain of experience. If process models are to be domain independent and if they are to be rapidly generable and modifiable, then we need to go away from experience based process model construction. Clearly, generation and modifiability relate to the process management policy adopted (see Usage World). Instantiation and assembly, by promoting modularization, facilitate the capitalisation of good practice and the improvement of given process models." Assembly The assembly technique is based on the idea of a process repository from which process components can be selected. Rolland (1998) lists two selection strategies: Promoting a global analysis of the project on hand based on contingency criteria (Example Van Slooten 1996) Using the notion of descriptors as a means to describe process chunks. This eases the retrieval of components meeting the requirements of the user / matching with the situation at hand. (Example Plihon 1995 in NATURE and repository of scenario based approaches accessible on Internet in the CREWS project) For the assembly technique to be successful, it is necessary that process models are modular. If the assembly technique is combined with the instantiation technique then the meta-model must itself be modular. Instantiation For reusing processes a meta-process model identifies "the common, generic features of process models and represents them in a system of concepts. Such a representation has the potential to 'generate' all process models that share these features. This potential is realised when a generation technique is defined whose application results in the desired process model." Process models are then derived from the process meta-models through instantiation. Rolland associates a number of advantages with the instantiation approach: The exploitation of the meta-model helps to define a wide range of process models. It makes the activity of defining process models systematic and versatile. It forces to look for and introduce, in the process meta-model, generic solutions to problems and this makes the derived process models inherit the solution characteristics. "The instantiation technique has been used, for example, in NATURE, Rolland 1993, Rolland 1994, and Rolland 1996. The process engineer must define the instances of contexts and relationships that comprise the process model of interest." Language Rolland (1998) lists numerous languages for expressing process models used by the software engineering community: E3 Various Prolog dialects for EPOS, Oikos, and PEACE PS-Algol for PWI as well as further