Model-based Explainable Coordination of Complex Reconfigurations

今天，软件工程师开发的系统能够在运行时对自己做出决策。例如，这种变化可以是在弹性云系统中配置和取消配置节点，以满足服务水平目标，或者改变单个无人机的飞行轨迹，作为无人机群的一部分，以实现某些群目标。这些系统有目标，也有一系列可能的行动。他们不断地通过执行所需的行动来实现给定的目标。该项目建议特别考虑将架构重构作为操作，即，通过添加或删除软件和硬件组件或更改其参数来改变系统结构的操作。不幸的是，在设计时仍然很难验证系统是否将在运行时适当地使用它们的重新配置。已经存在分析单个重构的方法。然而，在实践中，多个重构通常是独立开发和应用的。这可能会对整个系统产生负面影响和不必要的行为。重新配置之间相互作用的这种影响目前无法在运行时适当地建模或分析。这也导致对系统行为缺乏足够的可理解性，因为重新配置的应用和重新配置之间的相互作用是系统的自主决策，其原因不透明。因此，项目建议的主要研究问题是：“如何支持软件工程师开发应用复杂和协调的重新配置的经过验证且可解释的系统？”MENTOR将缩小这一差距。我们将为可解释的、复杂的、协调的、被动的和主动的重构开发一种建模方法和分析方法。这包括对先前工作的扩展，涉及建模不确定性、重新配置的预期效果以及协调重新配置的自动规划。此外，我们将提高预测可重构系统行为的工具的效率。最后，我们特别关注对重构行为的解释。这包括解释为什么要执行重新配置，为什么不执行，在重新配置协调期间做出决策的原因，以及紧急的、不协调的重新配置的原因。我们在项目中考虑了两个互补的领域和相应的示范：弹性云系统和系统的机电系统。关注这两个领域使我们能够区分可概括的方面和特定领域的结果。

Today, software engineers develop systems, which are able to make decisions about themselves at runtime. Such changes could for example be provisioning and deprovisioning nodes in elastic cloud systems to satisfy service level objectives or changing flight trajectories by individual drones as part of a drone swarm to achieve certain swarm objectives. Those systems have goals as well as a set of possible actions. They continuously aim at realizing the given goals by performing the actions as needed. This project proposal specifically considers architectural reconfigurations as actions, i.e., actions where the system structure changes by means of adding or removing software and hardware components or changing their parameters.Unfortunately, it is still difficult to verify at design time whether systems will use their reconfigurations appropriately at run time. There exist already approaches to analyze single reconfigurations. However, in practice usually multiple reconfigurations are independently developed and applied. This results in, potentially negative, influences and unwanted behavior of the complete system. Such effects of interactions between reconfigurations cannot be properly modelled nor analyzed at run-time at the moment. This also results in a lack of adequate comprehensibility of the system’s behavior since the applications of and the interactions between reconfigurations are autonomous decisions of the system and the reasons are not transparent.Hence, the main research question of the project proposal is:"How to support software engineers in developing validated and explainable systems which apply complex and coordinated reconfigurations?"MENTOR will close this gap. We will develop a modeling approach and analysis method for explainable, complex, coordinated, reactive and proactive, reconfigurations. This includes extensions of previous work with respect to modeling uncertainty, expected effects of reconfigurations as well as automated planning of coordinated reconfigurations. Furthermore, we will improve the efficiency of our tool which forecasts the behavior of reconfigurable systems. Finally, we specifically focus on providing explanations of the reconfiguration behavior. This includes explanations on why reconfigurations are executed – and why not, reasons for decisions during the coordination of reconfiguration as well as reasons for emergent, uncoordinated reconfigurations. We consider in the project two complementary domains and corresponding demonstrators: elastic cloud systems and mechatronic systems of systems. Focusing on these two domains enables us to distinguish generalizable aspects from domain specific results.