L. Hatvani, INTEGRAL CONDITIONS ON THE ASYMPTOTIC STABILITY FOR THE DAMPED LINEAR-OSCILLATOR WITH SMALL DAMPING, Proceedings of the American Mathematical Society, 124(2), 1996, pp. 415-422
The equation x '' + h(t)x' + k(2) x = 0 is considered under the assump
tion 0 less than or equal to h(t) less than or equal to (h) over bar <
infinity (t greater than or equal to 0). It is proved that lim sup(t-
->infinity) (t(-2/3) integral(0)(t) h) > 0 is sufficient for the asymp
totic stability of x = x' = 0, and 2/3 is best possible here. This wil
l be a consequence of a general result on the intermittent damping, wh
ich means that h is controlled only on a sequence of non-overlapping i
ntervals.