Equation Icon  [( ∫ T0 )2 (∫ T0 )2 ]1∕2 FF (ξ) ∼= max cos(ϕ (t;ξ) − ϕ′(t;ζ))dt + sin(ϕ (t;ξ ) − ϕ ′(t;ζ))dt .(120 ) ζ 0 0