랜덤 진동 용어: Ensemble(앙상블), Ergodic(에르고딕)

Ensemble (앙상블): A set of samples from the same experiments

Ergodic (에르고딕): Relating to a process in which sequence or sizable sample of energy is equally representative of the whole

Ergodicity of a Random Process 

- Weakly ergodic: Ensemble and time averages are the same in the estimation of mean and covariance

- Strongly ergodic: All the ensemble properties are deducible from the corresponding time average

예를 들어, 1000대의 장비 중 1대만 뽑아서 실험해도 1대가 1000대를 대표할 때 Strongly ergodic하다고 말한다.