Model-Based System Architecture, 2nd Edition

18Product Lines and Variants

Many systems exist in different configurations: a product line, a customized product, or different designs for trade studies. Typically, a single variant of a system affects only a few parts of the system. It is a slight derivation from the core system. However, it is impossible to quantify the number or level of detail that could vary to be still a variant of a system and not a completely new system.

This chapter provides a brief introduction to a broad field along with a couple of ideas. The broad field of product line engineering (PLE), model-based product line engineering (MBPLE), and variability management continue to evolve, and new literature is being published continuously [10, 87, 121].

A car and an aircraft could be a variant of a transportation system. In most cases, it makes no sense in practice to handle a car and an aircraft as variants of the same system and to manage all the appropriate relationships in a system model. The common parts of a transportation system are too abstract. Unfortunately, you cannot measure abstraction, and we cannot give an objective metric. You must decide if the abstraction levels of the common parts and the abstraction level of the variant parts are close enough to be valuable to be part of the same model. The benefit must be larger than the effort to manage the model.

The description of variants is a sophisticated task. It is already challenging to create a valuable model of a single system. Each variation ...