Who is the primary actor of an automated system?

In an automated black box trading application who should be identified as the primary actor in the use cases? Is i开发者_如何学运维t the system itself or the system administrator or the organization who has a vested interested in the system?

A system can be identified as such. According to Wikipedia

An actor in the Unified Modeling Language (UML) "specifies a role played by a user or any other system that interacts with the subject."

An actor is external to the system and interact with it; the organization is not an actor per se it is a stakeholder.

In this case the primary actor would be the stock market which send quotes to the automated trading system.

Your actor will be any system using your black box trading application.