## 5 Analysis
They are modeled using SysML requirement diagrams and requirement tables. The technique these authors use for RE is UML use-case diagrams. They focus on eliciting requirements. IDEA does not provide methods to deal with the dynamic evolution of IoT systems or for the security concerns of systems because it does not allow the user to represent different threats to systems. IoT-RML [39] is a modeling language that provides a means to devise requirement models for IoT systems. As far as RE is concerned, requirements are obtained from stakeholders and expressed as propositions. Requirements can be FRs or NFRs. FRs are considered with reference to one of the following parameters: detected variable, location, sending rate, and detection rate.Nonetheless, NFRs are represented as quality of service (QoS) parameters, which are measured based on specific metrics. Each metric has specific parameters. The authors define an IoT requirements domain model. IoT-RML is designed to be used for requirements specification and analysis. Conflicts among requirements are also considered. In the work presented in [46], the authors had the goal of analyzing the different characteristics of IoT systems and then studying the IDeA (IoT DevProcess & AppFramework), AgileIoT & Duttile, and design methodology (DM) methodologies used to design them. The IDeA methodology was adopted more than the other two approaches for the design and development of IoT systems. Furthermore, the authors contribute to the extension of the IDeA domain model so that it can support security aspects and mechanisms to make IoT systems secure. This proposal will be considered for systematic mapping because they performed a comparative analysis of three proposals for the development of IoT systems, of which IDeA considers RE activities. In another primary study [40], the authors propose a hybrid requirement modeling approach for an IoT application for ambient assisted living. The proposal covers the identification of requirements, modeling, design, and implementation phases. They propose a combination of different techniques to achieve this, such as templates for the documentation of requirements, UML use-case diagrams, SysML diagrams for specification, and SysML block definition diagrams for system design. Regrettably, this proposal is only for the development of IoT systems for ambient assisting living, and it is not a general methodology. The approach was recently created. It does not cover all phases of RE, but the authors remark that NFRs are covered by SysML models. In [31] the authors propose an approach associated with emerging RE techniques in the area of IoT-based smart applications. Regarding RE, different techniques are used for the phases involved in the RE process as techniques for stakeholder analysis, elicitation, analysis, specification, and validation. RE is carried out through five steps. First, the stakeholder analysis phase is carried out through the goal-question-metric method, taking into account distinct questions. Second, requirements elicitation is performed by means of a socio-technical method. Third, the analysis is performed using an interaction matrix (an interaction matrix finds interactions among several requirements and reveals conflicts). Fourth, interactive workshops are integrated with this RE framework for the specification of requirements and documentation. Finally, the validation is carried out by means of test-case design techniques. The primary study in [41] presents a method for the elicitation of requirements focused mainly on usability, security, and privacy, called TrustAPIS. Its goal is to increase the level of confidence in developing IoT projects. TrUStAPIS is an acronym that comes from using the first letters of each of the seven domains considered: trust, usability, security, availability, privacy, identity, and safety. RE uses goal-oriented modeling languages and JavaScript-based templates to elicit the requirements. It only provides support for elicitation but also considers NFRs and traceability support.