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1) цитируем Andries van Renssen (Gellish Modelling Method, Part 6, Knowledge and Product Modelling) 6. Functional Requirements & Process Design In the discrete component industry a design or specification starts with the definition of the functional requirements for the physical object (the discrete item). That is a specification of what the item is required to do. In the process industry a design or specification also starts with what is required to be done. However, there it is called ‘process design’ and that is described in terms of the processes that take place in the fluids, signals and energy that need to flow through the future discrete items in order to achieve the intended objective. These two approaches and two sets of terminology can be harmonised and described by using the same mechanisms as described below! In the ‘discrete component’ industry approach the term ‘function’ indicates “what should be done and which roles should be fulfilled”. In other words which activities, or behaviours are required and what roles the items should play in those activities or behaviours. Such an ‘activity’ or ‘behaviour’ can be active, such as in a machine, or passive, such as in a building, where a wall or beam should bear a load. In both cases the item has a behaviour in terms of motion and/or elastic or plastic deformation. The interaction between discrete items is expressed in terms of load and/or energy flows, signal flows and sometimes in terms of fluid flows. In this approach, a ‘pure’ functional description describes the required behaviour without defining the type of discrete items that perform the roles. In other words a functional design describes the activities or behaviour of discrete items (physical objects) and their roles. Strictly speaking those physical objects should not be classified in pure functional description, but in practice they are usually classified on a rather high level. Often a functional design does make the loads, fluids and energy flows and their classification explicit. In the ‘process’ industry approach, the description of the behaviour of its discrete components is preceded by a description of ‘the process’, which appears to be the behaviour of the fluids, signal flows and energy flows and sometimes loads, together with the roles which which should be played by the discrete items that enable the behaviour of the fluids. Passive ‘activities’ also appear, such as in storage or support processes. The interaction between processes is described by energy flows, fluid flows or signals, which are output of one process (activity) and input to another process (activity). Finally the connections between discrete items are used to describe mutual loads. Gellish defines an ‘activity’ as something that happens, or as a transition from one state to another. Therefore, it sees ‘behaviour’ as well as ‘process’ as subtypes of ‘activity’. This means that both approaches, the ‘functional design’ and the ‘process design’ can both be described as an activity in which physical objects, such as energy flows, signals and fluids play various roles.