8. The system of claim 7 , wherein the hierarchically arranged nodes correspond to a set of atomic dialogue activities of a complex dialogue activity with which the hierarchical dialogue structure associates the conversation.
8. The system of claim 7 , wherein the hierarchically arranged nodes correspond to a set of atomic dialogue activities of a complex dialogue activity with which the hierarchical dialogue structure associates the conversation. 10. The system of claim 8 , wherein: the processing circuitry is configured to, in response to one of the first dialogue moves, select one of a plurality of complex service activities according to which to provide the service; the selected complex service activity includes a plurality of atomic service activities; at least one of the atomic service activities is performed using information obtained from at least one of the first dialogue moves; and at least one of atomic dialogue activities is performed using information obtained as an output of the execution of at least one of the atomic service activities.