@article{SahlmannClemensNowaketal.2020,
  author    = {Sahlmann, Kristina and Clemens, Vera and Nowak, Michael and Schnor, Bettina},
  title     = {MUP},
  series = {Sensors},
  volume    = {21},
  journal   = {Sensors},
  number    = {1},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {1424-8220},
  doi       = {10.3390/s21010010},
  pages     = {21},
  year      = {2020},
  abstract  = {Message Queuing Telemetry Transport (MQTT) is one of the dominating protocols for edge- and cloud-based Internet of Things (IoT) solutions. When a security vulnerability of an IoT device is known, it has to be fixed as soon as possible. This requires a firmware update procedure. In this paper, we propose a secure update protocol for MQTT-connected devices which ensures the freshness of the firmware, authenticates the new firmware and considers constrained devices. We show that the update protocol is easy to integrate in an MQTT-based IoT network using a semantic approach. The feasibility of our approach is demonstrated by a detailed performance analysis of our prototype implementation on a IoT device with 32 kB RAM. Thereby, we identify design issues in MQTT 5 which can help to improve the support of constrained devices.},
  language  = {en}
}
@misc{SahlmannSchwotzer2018,
  author    = {Sahlmann, Kristina and Schwotzer, Thomas},
  title     = {Ontology-based virtual IoT devices for edge computing},
  series = {Proceedings of the 8th International Conference on the Internet of Things},
  journal   = {Proceedings of the 8th International Conference on the Internet of Things},
  publisher = {Association for Computing Machinery},
  address   = {New York},
  isbn      = {978-1-4503-6564-2},
  doi       = {10.1145/3277593.3277597},
  pages     = {1 -- 7},
  year      = {2018},
  abstract  = {An IoT network may consist of hundreds heterogeneous devices. Some of them may be constrained in terms of memory, power, processing and network capacity. Manual network and service management of IoT devices are challenging. We propose a usage of an ontology for the IoT device descriptions enabling automatic network management as well as service discovery and aggregation. Our IoT architecture approach ensures interoperability using existing standards, i.e. MQTT protocol and SemanticWeb technologies. We herein introduce virtual IoT devices and their semantic framework deployed at the edge of network. As a result, virtual devices are enabled to aggregate capabilities of IoT devices, derive new services by inference, delegate requests/responses and generate events. Furthermore, they can collect and pre-process sensor data. These tasks on the edge computing overcome the shortcomings of the cloud usage regarding siloization, network bandwidth, latency and speed. We validate our proposition by implementing a virtual device on a Raspberry Pi.},
  language  = {en}
}