Semantic Web in Internet of Things (IoT)

Things in the Internet of Things (IoT) are usually equipped with sensors or an actuator. Sensors enable to measure e.g. temperature, air humidity, light, motion, etc. Furthermore things can connect to the other things. However there is no interoperability standard for connecting heterogeneous devices from different vendors in the IoT. Instead there are several consortia and vendors which work on their own solution, (e.g. Smart Home standards).


One particular challenge in the Internet of Things is the management of many heterogeneous things. The things are typically constrained devices with limited memory, power, network and processing capacity. Configuring every device manually is a tedious task. We propose an interoperable way to configure an IoT network automatically using existing standards. The proposed NETCONF-MQTT bridge intermediates between the constrained devices (speaking MQTT) and the network management standard NETCONF. The NETCONF-MQTT bridge generates dynamically YANG data models from the semantic description of the device capabilities based on the oneM2M ontology.

System-Architecture with MQTT and NETCONF
Fig.1: System-Architecture with MQTT and NETCONF

Figure 1 illustrates three use cases: discovery mechanism of IoT devices, an actuator and a sensor scenario. Steps 1.-4. are executed only once upon device discovery. The microcontroller board, as a constrained IoT device, publishes an ontology-based device description to the MQTT broker. NETCONF server receives this message and converts it to the YANG Model which can be interpreted by the NETCONF client. Steps 5.-7. are necessary to control an actuator, e.g. to switch on the led. The RPC call will be translated to a MQTT topic and a message destined for the microcontroller board. Step 8. shows that the client can subscribe to the periodically publishing sensor values.


For further details please refer our publications.


Related Work

We see our work on semantic interoperability related to the IRTF Thing-to-Thing Research Group and the W3C Web of Things Interest Group.


Publications

Ontology-based Virtual IoT Devices for Edge Computing
Kristina Sahlmann and Thomas Schwotzer
8th International Conference on the Internet of Things (IoT)
Santa Barbara, California, USA, October 2018


Binary Representation of Device Descriptions: CBOR versus RDF HDT
Kristina Sahlmann, Alexander Lindemann and Bettina Schnor
Technical Report, 17th GI/ITG KuVS Fachgespräch: Drahtlose Sensornetze
Braunschweig, Germany, September 2018


Ontology-driven Device Descriptions for IoT Network Management
Kristina Sahlmann, Thomas Scheffler and Bettina Schnor
3rd Workshop on Interoperability and Open-Source Solutions for the Internet of Things (InterOSS-IoT)
Bilbao, Spain, Germany, June 2018


Managing IoT device capabilities based on oneM2M ontology descriptions
Kristina Sahlmann, Thomas Scheffler and Bettina Schnor
16th GI/ITG KuVS Fachgespräch: Drahtlose Sensornetze
Hamburg, Germany, September 2017


The Ad hoc Semantic Internet Protocol (ASIP) for Constrained Devices
Kristina Sahlmann, Thomas Schwotzer and Bettina Schnor
Accepted for 15th GI/ITG KuVS Fachgespräch "Drahtlose Sensornetze"
Augsburg, Germany, September 2016


MOCAP: Towards the Semantic Web of Things
Kristina Sahlmann and Thomas Schwotzer
11th International Conference on Semantic Systems
Aachen, Germany, 2015


Semantische Interoperabilität in Sensornetzen
Kristina Sahlmann and Thomas Schwotzer
Nachhaltige Mobilität, Energiewende und Industrie 4.0, ISBN: 978-3-8305-3575-1
BWV Berliner Wissenschafts-Verlag, 2015