## 5 Analysis  
In this section we present an analysis of the primary studies found. The aim of this section is to discuss in detail the strengths and weaknesses that were analyzed in each primary study. The entire approach was related to RE in IoT software systems development. This involves more than simply answering the research questions. In [30], the authors present RETioT (Requirements Engineering Technology for IoT software systems), which is a software technology designed for the creation of the requirement specification documents for IoT software systems to be built. RETioT aims to offer systematic, technical, and tool support for constructing requirements documents for IoT systems. RETioT involves the different RE phases detailed in Section 2, adapting their activities to the reality of IoT systems. It consists of eight phases: IoT ideation and conception, IoT procurement, IoT analysis, IoT specification, IoT verification, negotiation, IoT evaluation, and management. It is essential to mention that this is not a complete methodology; it is dedicated to creating a requirements specification document covering RE activities through UML use cases, considering NFRs. The authors in [44] present a systematic mapping study (SMS) to investigate techniques for the elicitation of functional requirements (FR) in IoT software systems. The authors aimed to classify the RE techniques, tools, and models applied for supporting the elicitation of FRs in the IoT field. The objective of this SMS was to update opinions regarding RE in IoT by including the views of experts. The authors state that this can support software quality as it addresses the gaps in traditional requirements elicitation techniques in the IoT field. Regrettably, that work only focuses on elicitation, whereas the present work studies all RE activities with the taxonomy that is presented in Section 2. Moreover, it presents an analysis of the primary studies found and suggestions for future research. In [32] the authors present the definition of an RE process for IoT systems. This process is an adapted and corresponding version of ISO IEC/IEEE 12207:2017. The RE process begins with identifying the context of the use of the IoT system, obtaining the stakeholders' requirements, prioritizing the requirements obtained, and elaborating the final list of the stakeholders' requirements. The RE guide detailed in this work is a preliminary one. In this regard, it requires application for its assessment in real-world projects in order to correct its deficiencies. The RE techniques are based on scenarios and UML use-cases. In the work presented in [47], the authors focus on the frameworks for security requirements in IoT cyber-physical systems (CPSs). They state that there is currently no framework for this task. They start with the assumption that the developer and the requirements analyzed in this type of system must broaden their analysis vision and consider the hardware perspective. This includes network security and the sensors that will be used. The author argues that most proposals for software engineering processes in this system focus only on the software part. The authors thus propose and evaluate an incremental security requirements evolution approach, configuring several components of different types to generate a secure system. To achieve this, they build a CPS RE framework for security, solving the problem of eliciting security requirements for different CPS sensors, gadgets, and components. Ultimately, the proposal only focuses on eliciting security requirements, rather than considering the RE phases detailed in Section 2. It is a framework for security requirements in CPS. It is not a requirements engineering methodology or an IoT software systems development proposal. The primary study introduced in [34] is focused on privacy. The authors point out that there are several approaches to helping professionals to analyze system privacy in the design phase. Nevertheless, it is a difficult task, particularly in IoT scenarios.