Home / Building Automation Environment Architecture Enabling Interoperability, Flexibility and Reusability

Abstract

The home / building automation environment is characterized by a high degree of heterogeneity with a large number of systems that need to interoperate, comprising different devices provided by various vendors. A need for greater integration, flexibility and interoperability is increasingly expressed. The current paper presents an architecture that utilizes three predominant state-of-the-art technologies, namely workflows, ontologies and web services in order to address the above need in an efficient way. I. INTRODUCTION Modern design in Building and Home automation has revolutionized the home environment, introducing a plethora of smart appliances as well as various network technologies, mandating an increase in the level of flexibility and interoperability. A great number of systems and applications exist with reference to this technological area, covering the whole range of the home - building automation system hierarchical model. This model comprises three different levers: the automation layer, the control layer and the service provision layer. The model that is described in this paper applies both to home automation and building automation applications; thus henceforward a reference to anyone of them is valid for both of them. The model is depicted in figure 1. The automation layer comprises the building automation equipment, such as sensors, actuators, smart devices and modules, controllers (PLCs) and network controllers. Automation level devices provide device relevant application code, that handles the required preprocessing, supporting the lower layer code for integrated systems addressing the provision of building and home services related to BMS, safety, security and disease management processes. The flow of information between automation level devices is usually characterized by time constraints, thus mandating the utilization of special communication protocols such as Lonworks, EIB, WorldFIP. The control layer includes devices that play the role of the control point of the home systems, wherein reside applications that are traditionally characterized as control automation applications. Control layer devices need to interconnect both with the indoor individual networks of the automation layer, as well as provide the necessary entry point through the internet to the upper layer for the provision of services to the home / building environment by third party Service Providers. The upper layer of our model refers to the various services offered by independent Service Providers that a building automation system can be a client of. A service can be offered either for free or be billed to its clients / users. Each user can be simultaneously a client of various services, while each service provider may have a bundle of services provided to each client. Internet plays a significant role in the overall communications for the enforcement of the presented model. The ubiquity of the internet has led to the emergence of standards that allow the creation of a unifying infrastructure that makes possible the integration of the different systems at whatever layer they may reside in. Nevertheless a conceptual dividing line exists between applications at the lower and the higher levels. The work presented in this paper is associated with a view of the home environment that mandates the integration and interoperability of all the systems / applications that participate in it, independently of their level. Architectural elements of this approach are presented describing home automation integrated services as processes by means of workflows, utilizing the state-of-the-art technology of Web Services in order to open up building automation systems and make available their functionalities. Our approach introduces innovation in the home environment through the incorporation of semantic information related with the home automation process, described in ontologies, increasing the overall degree of