The other scoring method is knowledge-based scoring functions, which use statistical analysis of protein complex structures. These functions model uncommon atoms, such as sulphur-aromatic. They also work on the statistical analysis of the ligand-target 3D complex structure. For example, Bleep, DrugScore, PMF, and SMoG are the most common knowledge-based scoring functions ( ). Knowledge-based scoring functions have demonstrated satisfactory performance in molecular docking programs.