x O m k + x O m k x O m k + x O m k m v 0 k 1 k 2 m k m k h l (H.1) m M k k 2 k 1 m m k α k h x O m M k h m M x O x O k h 0 M 1 M 2 r R k m m k m k k m k L 2 L 1 B A m m 2 m 1 k k 2 k 1 m m k k 2 k 1 m k m m l l k m A B α l m I R O n P r P r t P r M R r O Q α α A B O Q x P M O ϕ tω + ϕ x O O M x x R r 0 G Q R r 0 G Q P r α x t t W O T 4 T 2 2 2 1 m A 4 ω 2 2 1 m A 2 ω O T 4 T 2 t ñ W 2 2 1 m A 4 ω 2 2 1 m A 2 ω M l α h s