In this paper, we present a semantic network model (SNM) as a reasoning engine for the requirements models. The SNM consists of the vertices and the edges, in which they store information of the models and their interrelations. The SNM, through a semi-automated normalisation process, helps the user (1) to assign states to the models and their relations as to whether they can be included, excluded, or undecided, (2) to eliminate redundant interrelations, (3) to avoid over-specification, and (4) to visualise a simplified overview of the whole system. Finally, we formulate the well-formedness of the SNM, which indicates whether the given models can produce a formal specification. We also evaluate our techniques using several case studies.

In this paper, we present a formal definition of the integration of the requirements modeling language Behavior Trees (BTs). We first provide the semantic integration of two interrelated BTs using an extended version of Communicating Sequential Processes. We then use a Semantic Network Model to capture a set of interrelated BTs, and develop algorithm to integrate them all into one BT. This formalisation facilitates developing (semi-)automated tools for modeling the requirements of large-scale software intensive systems.