The interaction type approach to relationships management

One important paradigm proposed in literature by the scientific community that advocates the viable system approach is the structure-system dichotomy for the capability to simplify the investigation of a phenomenon and recognize its scope and implications. The purpose of this paper is to provide a contribution to the debate which concerns the structure-system approach introducing the concept of interaction type as a bridge linking the relationship concept to that of interaction. The interaction type is first introduced in its simplest form using an UML class diagram that points out its role when the observer views changes from structure to system and from system to structure. Then, the recursive nature of interaction types is discussed in order to show how complex relationships, that involve more parties at several interaction levels, can be better represented and used. Finally, a model for the representation of transactions is proposed in which a transaction type can be interpreted as a particular case of interaction type and a transaction as an ordered set of interactions. Two case studies are presented in the paper; the first concerns an example of fund transfer and highlights how the interaction type hierarchy can be applied. The second case study is from the port community system of South Italy and shows how a clearance to enter or leave national waters can be described as departure from and arrival to interaction types.