  The notion of the black hole singularity and the proof of the singularity
theorem were considered great successes in classical general relativity.
Singularities had presented deep puzzles to physicists. Conceptual challenges
were set up by the intractability of the singularity. The existence of black
hole horizons which cover up the interior, including the singularity of the
black hole from outside observers, builds an information curtain, further
hindering physicists from understanding the nature of the singularity and the
interior structure of black holes. The regular black hole is a concept produced
out of multiple attempts of establishing a tractable and understandable
interior structure for black hole as well as avoiding the singularity behind
the black hole horizon. A method is needed to check the correctness of the new
constructions of black holes. After studying the Hawking radiation by fermion
tunnelling from one type of regular black hole, structure dependent results
were obtained. The result being structure dependent points out the prospects of
employing the Hawking radiation as a method to probe into the structure of
black holes.
