Using Reference Architectures for Design and Evaluation of Web of Things Systems: A Case of Smart Homes Domain

Web of Things (WoT) provides abstraction that simplifies the creation of Internet of Things (IoT) systems. IoT systems are designed to support a number of ubiquitous devices and management subsystems. The devices and subsystems can be a part of safety critical op- erations as well as smart management of multiple actuators that control the smart home devices. The devices and subsystems need to comply to standardized business and quality requirements of a specific IoT domain. Designing subsystems and actuators for the individual devices as independent software can result in lack of standardization, which can neg- atively impact the overall quality of a WoT system. Standardisation of the IoT applications and subsystems constituting a WoT system can be facilitated by providing a standardisation at the architecture level. As using Reference Architectures (RA) is a well established ap- proach to achieve architectural standardisation, using the RA for designing IoT subsystems and WoT system can facilitate standardisation of the architecture of individual subsystems constituting a WoT system as well as standardisation of the WoT system. The aim of the research presented this chapter is to provide insight to the process of using a RA for anal- ysis, design, evaluation and evolution of the IoT subsystems as well as a WoT system. We present a software process-based approach to use a RA for architecture design of individual IoT subsystems and then use the IoT subsystems for architecture design of a WoT system. We use a case study-based research approach to analyse application of the process for de- sign, evaluation and evolution of the IoT subsystems and the WoT system for smart-homes domain. The applications of the presented approach is analysed with reference to secu- rity and energy management in smart homes. The results of the case studies show that (i) the IoT RA can be used for the initial design to incorporate the standardized business and quality requirements, (ii) the elements of the concrete IoT subsystems architectures can be included in the IoT RA for evolution of the RA with respect to emerging and domain specific requirements, and (iii) open discussion by including architects of all IoT subsystems to determine key business and quality requirements of IoT subsystems can play an important rule in the evaluation of the IoT subsystems as well as evolution of the IoT RA. We foresee that the presented approach can be used for the analysis, design, evaluation and evolution of the IoT subsystems and WoT system even if the detailed architecture design activities of the IoT subsystems are carried out independently.