The process of design optimisation is a special form of design synthesis characterised by a high level of specificity with respect to its goals. As such it relies on the following supporting elements: measurable goals -clear and quantifiable statement of goals to enable evaluation of candidate designs.design variability -the system design must present amenable elements. In the context of system design the change may be made at various levels: topology of component arrangement, interchangeable components, configuration within a component.constraints -restrictions, such as budgeted cost and time, provide an essential definition of design feasibility which effectively reduces the search space to a manageable size.
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Bayesian Network 110Currently, all prevalent approaches to architectural system design can be separated into two groups based on their main artefacts: quality-driven and model-driven (Parakhine, 2009, p. 22). The quality-driven design synthesis process focuses on extensive analysis of qualities and possible trade-offs. It necessitates creation of goal descriptions expressed partially in terms of choices required to attain them, which in turn contributes towards the evaluation of the candidate architectures. On the other hand, the model-driven methodology concentrates on representing the system design from the point of view of a specific domain (e.g. security) with consequent modification through application of well-defined domain-specific changes. Although the two groups operate on different artefacts, both of them fit into the same general structure of an architectural optimisation process shown in Figure 1. Fig. 1. A generic process of system optimisation at an architectural level.In its simplest terms, the process of architectural optimisation can be characterised as one based on iterative derivation and evaluation aimed at satisfaction of multiple goals. The fields of computer science and system design offer a wealth of frameworks exhibiting features and capabilities of the optimisation process shown in Figure 1. Table 1 details how the requirements for facilitation of architectural optimisation have been addressed by some of the various frameworks built specifically for that purpose or built to solve general design problems in a way which makes optimisation possible. The described optimisation approaches adopt various methods and techniques to attain their goals and produce the outcomes. Those relevant to the system design process are listed below. The presented features and techniques are grouped by the element of the optimisation process (Figure 1) whose function they were used to fulfill:Genetic Algorithms -indicates that the framework performs evolutionary search that relies on encoding of system design in the form appropriate for breeding operators.Meta-Heuristics -shows that the framework was created around a specific optimisation heuristic, such as simulated annealing or a tabu-search.Function Analysis -identifies frameworks that employ a mathematical function analysis to ...