Central Optimisation Engine (XXX). Function The Central Optimisation Engine is the driver of the optimisation process, responsible for exploring the design space (by choosing which encodings to evaluate) and for collecting the best solutions so far. The XXX will use genetic algorithms based on HiP-HOPS technology, but HiP-HOPS itself will only be used as an analysis tool. Instead the intention is to create a new implementation that can more tightly integrate with the other elements of the optimisation architecture (e.g. in the form of a Papyrus plugin). When optimisation is required, the optimisation engine receives from the OSDM a tree containing the different variation points in the model together with a set of optimisation objectives. This is the master encoding, the base DNA of the model to be optimised. To perform optimisation, the optimisation engine chooses a particular encoding (by selecting which variation points to use and which not to use according to its internal heuristics) and passes this on to the VRM. The VRM returns a version of the original model with the variability resolved (although product line variability may still be unresolved). This resolved model is then passed to the plugin interfaces to the various analysis engines (timing, safety, cost etc), according to the optimisation objectives. Once complete, the analysis results are returned so the optimisation algorithm can evaluate them against its objectives and then repeat the cycle. Inputs For starting optimisation: • A set of optimisation parameters. These should specify which analyses are to take place (e.g. safety, timing) and with which tools, which particular attributes are to be optimised (e.g. cost, reliability, schedulability etc), and whether to maximise or minimise those objectives. Any constraints may also be included here (e.g. a minimum level of safety, a maximum cost etc). The set of optimisation parameters comes from the user (requiring some kind of user interface). • The Master Encoding Hierarchy, which describes all the variability points in the model. The master encoding tree should be provided by the OSDM. It is likely to be in XML format and provided in-memory (but there are other alternatives). During optimisation, in each iteration the engine receives: • A resolved model; after passing the current encoding to the VRM, the optimisation engine receives a model with the variability resolved accordingly. It can then pass this to the analysis plugins. • The set of analysis results for each objective;...
