Making sense of standards: An evaluation and harmonisation of standards in the Sensor Web

Sensor data plays a significant role in our life. Sensors are devices that can sense our environment. This sensor data is part of the Sensor Web and needs a vast data infrastructure design, because many organisations are involved, the abundance of different sensors and because of the big volume of data and near-real time data. The extent to which sensor data can be used depends on a variety of factors, among them the observations of the sensor, the data about the sensor itself and interoperability between sensor systems. Standards will lead the way to a well-functioning interoperable Sensor Web, meaning all the systems can communicate with and understand each other. Therefore, the sensor standards need to be discoverable, interoperable and usable in their own domain. Currently this is not yet the case. There is not sufficient information available about the gaps and overlaps in the Sensor Web and there are a lot of different standards and therefore the systems are not capable of communicating to each other. Currently the standards are made and maintained by different organizations. There is one cluster of standards assembled by Open Geospatial Consortium (OGC), called Sensor Web Enablement (SWE), which forms the spine of the Sensor Web, but there are also other non-OGC standards that are useful for the Sensor Web, such as the IEEE standards and W3C's Semantic Sensor Network. A use case demonstrates both the usefulness and the gaps and overlaps of the standards in the Sensor Web, because it sketches a real-life situation in which standards can bring interoperability. The Smart Emission project in Nijmegen is a suitable candidate to assist in answering questions regarding sensor standards. In Nijmegen there is a citizen request for air quality data. The Smart Emission Project was initiated to respond to this request. The project is a collaboration between different organizations to to keep the city liveable by incorporating citizen participation in the Sensor Web. Sensors that measure different environmental indicators namely air quality, sound pollution, and meteorological data are placed all over Nijmegen to sense the city. The plan is to provide the data to the citizen for both viewing and downloading via applications. The project team is currently using OGC sensor standards, namely the SensorThingsApi and Sensor Observation Service, but is interested in alternatives, such as for remote access to the sensor, and can profit from research on sensor standards. The requirements for implementation in the use case are extracted from meetings with citizens, network maintainers, experts in the Sensor Web and project members. Validation of requirements from the Smart Emission project demonstrates weaknesses and strong points in the current standards and how they can be used in a combination to provide the right data to the citizen. Validation is done through a data model based mainly on Observations and Measurements. Results show that not all requirements for the use case are met and that standardisation is not achieved for every requirement. To improve standardisation for future projects the adapted Open Systems Interconnection (OSI) model in combination with a digital sensor portal is suggested to be used. The OSI model, adapted from computer science and used for data interoperability on the Internet is an ordering system and can indicate the right standard for the right usage. It is a layered system in which data is added in all the five layers. The chosen data flows through this system and ends up with relevant information for the user and the system. The adapted OSI-model is changed on several aspects. The layers are different than the original OSI-model. Furthermore division between standards is made by categorizing them on implementation method. Using the Adapted OSI-model will fill the gaps and demonstrate the overlaps in the Sensor Web make it more interoperable. In this thesis data modeling of a use case has been used to analyse sensor standards. The results show that in the current situation the sensor standards are insufficient ordered, interoperable and harmonised. The Adapted OSI-model can bring order and the model can open up the way towards a more interoperable sensor web.Architecture and The Built EnvironmentOTBGeomatic

Exploring Photogrammetric Point Clouds

UrbanismArchitecture and The Built EnvironmentGeomatic