Availability and reliability evaluation of an IoT system : hierarchical modelling for smart buildings

Abstract

The Internet has been undergoing significant transformations and changing the world around it. We can also see the internet is used in many areas and innumerable purposes, even by objects. This evolution leads to the definition of the Internet of Things (IoT) concept. It is a system composed of storage resources, sensor devices, controllers, applications, and network infrastructure, to provide some service to its users. Since IoT comprises heterogeneous components, the creation of these systems, as well as the communication and maintenance of their components, becomes a complex task. There are growing interest and efforts of academia and industry in areas such as smart cities, smart homes, and industry 4.0, which may be seen as IoT-related concepts. This dissertation presents a sensitivity analysis of a system of IoT, considering distinct infrastructures and models to assess their availability metrics. A case study was carried out based on different scenario considering a smart building. The proposed models enable us to estimate measures such as steady-state availability. Thus, it was possible to notice a gain of availability in the system when applying redundancy to a local management infrastructure. Besides, there was a gain of availability when considering cloud computing infrastructure to manage system comprising two or more buildings. Sensitivity analysis revealed the components that most affect the availability. I also performed a comparative analysis of budget costs between on-premises and cloud-based management infrastructures. This study considered a smart photovoltaic system, where the previous reviews served as the basis for the proposed system. Besides, was evaluate the deployment cost and obtained economy. Thus, it was possible to notice that there was no considerable gain of availability in the system when applying grid-tie solar power or off-grid solar power. The grid-tie solar power system is cheaper than the off-grid solar power system, even though it produces more energy. However, in our research, we were able to observe that the off-grid solar power system recovers the applied financial investment in smaller interval of time.