Reliability, Availability, Maintainability, and Safety/Security (RAMS) analysis of Critical Infrastructures (CIs) can be applied to investigate their performance subjected to failure modes. The literature has witnessed earlier research approaches to RAM analysis. However, the integration of cybersecurity or safety aspects, along with the RAM to develop RAMS analysis methods, tools, and models, is a significant aspect for protecting CIs as their digitalization is progressing. In recent times, digital components and systems comprising information and communication technologies, smart devices, efficient gateways, faster protocols have transformed the CIs. This transformation comes with a considerable cost, such as the necessity to integrate innovative cyber-defense measures and policies due to new vulnerabilities, efficient maintenance strategies, risk management scenario development, resilience with self-healing architecture. Nevertheless, the current knowledge body lacks an up-to-date Systematic Literature Review (SLR) focused on addressing integrated protection aspects, recent developments, and evaluation criteria towards RAMS analysis for CIs. Accordingly, this study aims to provide a comprehensive SLR on existing studies dealing with developing techniques, methodologies, protocols, models, and RAMS analysis tools for different applications. This SLR followed the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. 1513 records published between 2011 and 2020 are initially identified, which are later screened to 212 records to be considered for the eligibility check process. Finally, after examining the exclusion and inclusion criteria, a total of 19 articles are included in this research. In this SLR, a comparative analysis of existing solutions based on included studies is presented in different aspects such as developed architectures and methodologies, performance evaluation mechanisms, implementation scenarios, targeted applications, pros and cons, and applied CIs protection aspects associated with RAMS. The findings suggest that RAMS analysis for CIs is an emerging research area, with currently focused applications including power grid stations, Cyber-Physical Systems, cloud computing, maritime transportation, and Industrial Control Systems. 36.8% of the studies have performed a real-time implementation, while the remaining approaches have either performed simulation or preliminary analysis. Also, 84.2% of the included studies focus on integrating only three aspects of CIs protection. Finally, the open research challenges and limitations of existing studies and their respective emerging solutions are presented.

关键基础架构（CI）的可靠性，可用性，可维护性和安全性（RAMS）分析可用于调查其在故障模式下的性能。文献见证了RAM分析的早期研究方法。但是，随着CI的数字化发展，网络安全或安全方面的集成以及用于开发RAMS分析方法，工具和模型的RAM是保护CI的重要方面。近年来，包括信息和通信技术，智能设备，高效网关，更快协议的数字组件和系统已经改变了CI。这种转变会带来巨大的成本，例如由于新的漏洞，有效的维护策略，风险管理方案开发，具有自我修复架构的弹性。但是，当前的知识机构缺乏针对于综合保护方面，最新发展以及针对CI的RAMS分析的评估标准的最新的系统文献综述（SLR）。因此，本研究旨在针对涉及不同应用的开发技术，方法，协议，模型和RAMS分析工具的现有研究提供全面的SLR。该SLR遵循了系统评价和荟萃分析首选报告项目的建议。最初确定了2011年至2020年之间发布的1513条记录，然后筛选出212条记录以进行资格检查过程。最后，在检查了排除和纳入标准后，本研究共包括19篇文章。在此SLR中，在不同方面（包括已开发的体系结构和方法，性能评估机制，实现方案，目标应用程序，优缺点和与RAMS相关的已应用CI保护方面）对基于包含的研究的现有解决方案进行了比较分析。研究结果表明，针对CI的RAMS分析是一个新兴的研究领域，当前的重点应用包括电网站，网络物理系统，云计算，海上运输和工业控制系统。36.8％的研究执行了实时实施，而其余方法则进行了模拟或初步分析。还有84 纳入的研究中有2％侧重于仅集成CI的三个方面。最后，介绍了现有研究及其各自新兴解决方案所面临的开放研究挑战和局限性。