A system for creating a semantic data warehouse including a convergence service configured to execute queries to connected data sources, to convert data from source to domain semantics, and to aggregate converted data. A push-button mechanism is provided on the outer cover of the camera to activate the transmitter when required. The current distribution can be regulated in a controlled manner and the return circuit of the melt current passes back via at least one other electroconductive element of the mould, which is electrically isolated in relation to a first part of the mould which forms the remelt ingot.