  Global IoT services (GIoTS) are combining locally available IoT resources
with Cloud-based services. They are targeting world-wide services. GIoTS
require interoperability between the locally installed heterogeneous IoT
systems. Semantic processing is an important technology to enable data
mediation as well as knowledge-based processing. This paper explains a system
architecture for achieving world-wide semantic interoperability using
international standards like oneM2M and the OMA NGSI-9/10 context interfaces
(as used in the European Future Internet Platform FIWARE). Semantics also
enables the use of Knowledge-based Semantic Processing Agents. Furthermore, we
explain how semantic verification enables the testing of such complex systems.
