1. A method of modeling a real-world modeled system with a system model in a data processing system, the method comprising: the data processing system constructing in the system model a multi-level hierarchy of Capabilities in the real-world system, each Capability including a Verb specifying an action and an Object acted on by the Verb; the data processing system constructing in the system model one or more multi-level Performer hierarchies, each Performer hierarchy including a plurality of Performers each having an associated lifecycle and at least one associated Capability, wherein each of the at least one associated Capability is one of a set including a provided Capability provided by the Performer and a required Capability required by the Performer; the data processing system constructing in the system model a multi-level Location hierarchy associating one of a plurality of Locations with each Performer in the one or more multi-level Performer hierarchies; the data processing system constructing in the system model a plurality of Capability Instances defining requirement and provision of Capabilities by Performers in the one or more multi-level Performer hierarchies; and in response to a query specifying a Location and a time, the data processing system outputting a view of the system model for the specified Location and time.