## 2 Methodology
### Research Questions  
To ensure a systematic and transparent scope, this review integrates the SEGRESS methodology with the PICOC framework. SEGRESS provides the overall structure for conducting systematic reviews in software engineering, including the stages of planning, execution, and reporting. Within this structure, PICOC (Population, Intervention, Comparison, Outcome, and Context) is applied during the planning stage to guide the formulation of research questions and the definition of inclusion and exclusion criteria.  
In this study, the Population consists of ROS-compatible robotics simulators used in the development of applications related to Industry 4.0 and Industry 5.0. The Intervention involves evaluating these simulation tools by analyzing their technical features, support for various robot configurations, and integration with key enabling technologies. The Comparison focuses on identifying the advantages and limitations of different simulators in relation to interoperability, technical requirements, and suitability for specific use cases within industrial contexts. The expected Outcome is that we will provide a structured understanding of the most frequently used ROS-compatible simulators, the technologies they enable or integrate, and their role in advancing Industry 4.0 and Industry 5.0 applications. The Context of the review includes industrial and manufacturing environments, where simulation is a critical component in the development, testing, and deployment of robotic systems.  
By combining SEGRESS and PICOC, this review ensures that the research questions are both methodologically rigorous and practically relevant. Based on this structured approach, the following research questions were formulated:  
RQ1: What ROS-compatible simulator platforms have been used for developing Industry 4.0/5.0 applications? RQ1 aims to identify the most commonly used ROS-compatible simulation platforms employed in the development of Industry 4.0/5.0 applications. Additionally, it seeks to present the reported advantages and disadvantages of each platform.  
RQ2: What are the most common applications in the Industry 4.0/5.0 domains developed using these simulators? RQ2 aims to identify and categorize the most frequently developed Industry 4.0/5.0 applications that leverage ROS-compatible simulation platforms. This research question seeks to identify the primary use cases in different robotics domains.  
RQ3: What are the commonly used robot configurations and key technologies that are integrated in these applications? RQ3 aims to identify the predominant robot configurations employed in Industry 4.0/5.0 applications. Additionally, this research question investigates the core technologies that enable these robotic systems, specifically focusing on sensing, perception, planning, mapping and control.  
RQ4: How have ROS 1 and ROS 2 been adopted in Industry 4.0/5.0 applications? RQ4 aims to examine the adoption trends of ROS 1 and ROS 2 in Industry 4.0/5.0 applications, identifying key differences and limitations of ROS 1 and ROS 2.  
RQ5: What are the additional communication and integration technologies that enable compatibility between simulators and modules used for developing Industry 4.0/5.0 applications? RQ5 investigates methods that facilitate efficient, scalable, and interoperable robotic systems. This research question aims to identify how state-of-the-art technologies have addressed the limitations of ROS and ROS 2 regarding connectivity.