The Specification part describes the design, among other things the functions (or functional requirements) of the robot. The use cases help to derive and explain these functions. For this, your use cases should be somewhat more elaborated. The human-robot interaction should be well explained, step by step, in the action sequences of the scenario. E.g., what should the NAO (be able to) do to initiate a conversation OR to let the subject initiate a conversation. And a step like “Subject interacts with NAO through conversation” is far too general (and do not use the word subject).
The Specification part describes the design, among other things the functions (or functional requirements) of the robot. The use cases help to derive and explain these functions. For this, your use cases should be somewhat more elaborated. The human-robot interaction should be well explained, step by step, in the action sequences of the scenario. E.g., what should the NAO (be able to) do to initiate a conversation OR to let the subject initiate a conversation. And a step like “Subject interacts with NAO through conversation” is far too general (and do not use the word subject).