Managing Conflicting Requirements in Systems of Systems

Software systems have evolved from being stand-alone systems to being composed into Systems of Systems. A System of Systems (SoS) is defined as an arrangement of independently created, discovered, and selected systems, which are integrated into a single system in order to deliver unique capabilities [1]. In this context, each participating system can operate and support different goals in its own environment (viz. local goals), as well as support new goals of the SoS as a whole (viz. global goals), that could not be achieved separately by the participating systems. An SoS presents many features including operational and managerial independence, geographic distribution of participating systems, and emergent behaviors [2]. Examples of SoSs are found in several different domains including, but not limited to, transport network systems, household energy management systems, personal nutrition management systems, smart homes, smart cities and intelligent healthcare systems. However, as the SoS is formed by the integration of independent complex systems, this will increase the complexity of the SoS to at least one more order than its component systems [3]. This means that problems in the SoS environment are harder to handle than in the component system environment. Therefore, this will bring a number of software engineering challenges regarding their specification, design, construction, and operation. Among these, one important challenge is concerned with managing emerging conflicting behavior that leads to inconsistency. In an SoS, the various participating systems are often from different domains; are developed by different teams of people under different circumstances and time; have distinct functionalities; and are used by different stakeholders. All of these factors contribute to the existence of inconsistent and conflicting requirements. This research presents an overview of a framework called MaCoRe_SoS (Managing Conflicting Requirements in Systems of Systems) that supports conflict management in SoSs. The management of conflicting requirements in the proposed framework involves three main steps, namely (a) conflict identification, (b) conflict diagnosis, and (c) resolution based on the use of a utility function. In order to support the main steps, the framework uses a Monitor-Analyze-PlanExecute-Knowledge (MAPE-K) architectural pattern[4]. II. MOTIVATING EXAMPLE