One of the primary drivers for self-adaptation is ensuring that systems achieve their goals regardless of the uncertainties they face during operation. Nevertheless, the concept of uncertainty in self-adaptive systems is still insufficiently understood. Several taxonomies of uncertainty have been proposed, and a substantial body of work exists on methods to tame uncertainty. Yet, these taxonomies and methods do not fully convey the research community's perception on what constitutes uncertainty in self-adaptive systems and how to tackle it. To understand this perception and learn from it, we conducted a survey comprising two complementary stages. In the first stage, we focused on current research and development. In the second stage, we focused on directions for future research. The key findings of the first stage are: a) an overview of uncertainty sources considered in self-adaptive systems, b) an overview of existing methods used to tackle uncertainty in concrete applications, c) insights into the impact of uncertainty on non-functional requirements, d) insights into different opinions in the perception of uncertainty within the community, and the need for standardised uncertainty-handling processes to facilitate uncertainty management in self-adaptive systems. The key findings of the second stage are: a) the insight that over 70% of the participants believe that self-adaptive systems can be engineered to cope with unanticipated change, b) a set of potential approaches for dealing with unanticipated change, c) a set of open challenges in mitigating uncertainty in self-adaptive systems, in particular in those with safety-critical requirements. From these findings, we outline an initial reference process to manage uncertainty in self-adaptive systems.

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自适应系统的不确定性：研究社区的观点

自适应的主要驱动力之一是确保系统实现其目标，而不管其在操作过程中面临的不确定性。然而，自适应系统中不确定性的概念仍未得到足够的理解。已经提出了几种不确定性分类法，并且在控制不确定性的方法方面存在大量工作。但是，这些分类法和方法并未完全传达研究界对自适应系统中的不确定因素是什么以及如何解决不确定性的看法。为了理解并从中学习，我们进行了包括两个互补阶段的调查。在第一阶段，我们专注于当前的研发。在第二阶段，我们集中于未来研究的方向。第一阶段的主要发现是：a）自适应系统中考虑的不确定性来源概述，b）用于解决具体应用中不确定性的现有方法的概述，c）洞悉不确定性对非功能性需求的影响，d）洞悉不同观点社区内部对不确定性的认识，以及需要标准化的不确定性处理流程以促进自适应系统中的不确定性管理。第二阶段的主要发现是：a）超过70％的参与者认为可以将自适应系统设计为应对意料之外的变化的见解； b）应对意料之外的变化的一组潜在方法，c）缓解自适应系统（尤其是对安全性有严格要求的系统）的不确定性方面的一系列公开挑战。