Cloud of Things based on Linked Data
IoT (Internet of Things) is a highly popular technology that is expected to play a pivotal role in the fourth industrial revolution, which is represented by the convergence of manufacturing and information and communications technologies. The topics of the fourth industrial revolution include connectivity, intelligence, and automation, and the IoT technology will serve as the foundation upon which to realize these three goals. According to the research firm Gartner, the number of IoT-related devices is expected to reach 25 billion by 2020. Through this, it is expected that the data produced by various types of sensors and devices in the IoT environment of objects will be enormous, i.e., big data, and will lead to a new era involving these vast amounts of data.
However, the IoT is associated with heterogeneity problems due to the existence of various devices. Leading vendors are working on standardization, but these processes are still in their nascent stages, and because too many vendors use different protocols, the devices are not interconnected and the data produced by the devices do not converge. In addition, IoTdevices have limited computing power and resources to handle big data.
To overcome the limitations of computing power and resources and to solve the heterogeneity problem, we combine the IoT and cloud and virtualize IoT devices in the cloud environment to utilize the CoT (Cloud of Things) concept, which maps the devices in the real world. It also interconnects the virtualized devices in the cloud to form a device mesh based on linked data which are both intelligent and automated.
- Linked Data
Linked data is a technology that connects data based on the Semantic Web standard technology of the World Wide Web Consortium (W3C). As current web pages are connected to each other, data can be expressed in a RDF (resource description framework) and can be connected to other data by means of various relationships. Anyone can access data through a URI (uniform resource identifier), which defines data in a form in which it can be read and processed by people and machines via the Web. Gartner announced the top ten strategic technologies in 2016, and the list included device meshes that can connect and interact with a variety of IoT devices. Gartner also mentioned the Semantic Web as a means by which to realize device meshes. Linked data can provide interconnections between various devices that produce different data. They are a type of technology that can find meaning in the big data era, during which a plethora of information is created, to realize connections, intelligence, and automation of the three main issues of the fourth industrial revolution. In this paper, we propose a method with which to construct device meshes by applying linked data to the IoT.
Ontology refers to a type of knowledge representation in which a computer understands the concepts expressed by the ontology and can process the knowledge. Typical ontology research for IoT domains includes SSN and IoT-Lite. The SSN ontology is one of the most significant and widespread models used to describe sensors and IoT -related concepts. However, SSN focuses on representations of sensors from a physical point of view and is heavy because there is no core essential. IoT-lite was designed based on the core aspects of SSN. Therefore, it is lightweight and suitable for the IoT domain but does not reflect the latest trends because there is no consideration of devices or data connections.
Finally the Internet of Things will be the foundation technology of the fourth industrial revolution, and Cloud of Things based on linked data is a type of technology that overcomes the limitations of the Internet of Things and allows connections, intelligence, and automation, which are the topics of the fourth