( ) = ( ) + [1 ( )] ( ) + [1 ( )]
( ) = 1 ( ) = 1
( ) = ( ) = 1 ( ) 0 ( ) 1 ( ) = x = Oi(Xi x) = Oi
( ), ( ) = 1 2. ( ) 2
R(tp) = 1 2 exp (tp ) tp R(tp) = 1 2 ( ) = ( ) + [1 ( )] ( ) + [1 ( )]