Measuring Semantic Distance between LWM2M Resources

Internet of Things (IoT) involves the interconnection of a variety of heterogeneous devices. Managing these diverse sets of devices is however extremely challenging. The Open Mobile Alliance has therefore standardized the Light Weight Machine to Machine (LWM2M) protocol that provides a uniform interface for controlling and managing these IoT devices. In certain usage scenarios, it is essential to identify the IoT devices that have similar properties as a group and control them with a single management command, so that they can substitute for each other in case any of them fails. In this paper, to measure the similarity between the manageable properties of any two IoT devices, we define a metric called LWM2M Resource Semantic Distance (LwRSD). LwRSD assigns weights to the properties of an IoT device based on a Set of Contextual Requirements (SCoRq) specified by the user. Using these weights, and based on the contextual requirements, the LwRSD calculates a specific "distance" between the two devices, said distance being an indication of the extent to which one device can be substituted for the other. From experimental evaluation on real IoT devices, our results show that we can successfully uncover similarities between resources that are not that straightforward to at first glance. For example, network connected TVs, coffee Machine and light-bulbs can be used as emergency warning systems in a building.