Fundamental concepts of controllability and observability for MIMO LTI systems. The observability and controllability of a system are mathematical duals. Controllability and observability are dual aspects of the same problem. Note that Iddq test inputs require only controllability, and not observability. Other aspects which are also studied are controllability and observability. Second, the circuit may be re-defined for better fault detectibility (improved controllability and observability). It quantifies the astronomical observability of celestial objects and the interference caused by light pollution. The other three are observability, recoverability, and task conformance. Redundancy is linked to the concept of observability. Let's now calculate the kernel of observability matrix. The craft is designed for low radar observability and can carry crew and payload internally. Marketing messages may also focus on compatibility and observability. Stealth technology (or LO for "low observability") is not one technology. Research continues into other ways of decreasing observability by radar. In many works, the agent is assumed to observe the current environmental state ("full observability").