Before revision:  The default event occurs in an expected or unexpected manner when the firm value reaches a certain lower threshold - the default barrier at predetermined discrete announcing dates or  at the first jump time of a Poisson process with given default intensity , respectively .
After revision:  The default event occurs in an expected or unexpected manner when the firm value reaches a certain lower threshold - the default barrier at predetermined discrete announcing dates or at the first jump time of a Poisson process with given default intensity given by a step function of time variable .