I ( Δ t ) = ∫ 0 Δ t   κ ( t ) d t          ( 4 )    MathType@MTEF@5@5@+=feaafiart1ev1aaatCvAUfKttLearuWrP9MDH5MBPbIqV92AaeXatLxBI9gBaebbnrfifHhDYfgasaacH8akY=wiFfYdH8Gipec8Eeeu0xXdbba9frFj0=OqFfea0dXdd9vqai=hGuQ8kuc9pgc9s8qqaq=dirpe0xb9q8qiLsFr0=vr0=vr0dc8meaabaqaciaacaGaaeqabaqabeGadaaakeaacqWGjbqscqGGOaakcqqHuoarcqWG0baDcqGGPaqkcqGH9aqpdaWdXaqaaGGaciab=P7aRjabcIcaOiabdsha0jabcMcaPiabbsgaKjabdsha0bWcbaGaeGimaadabaGaeuiLdqKaemiDaqhaniabgUIiYdGccaWLjaGaaCzcamaabmaabaGaeGinaqdacaGLOaGaayzkaaaaaa@44AD@