“…Many researchers studied the δ − shock model in the last 20 years or so. Lam and Zhang, 6 Rangan et al, 7 Li and Kong, 8 Li and Zhao, 9 Ma and Li, 10 Liang et al, 11 Eryilmaz and Bayramoglu, 12 Zhu et al, 13 Eryilmaz, 14,15 Tuncel and Eryilmaz, 16 Liu, 17 Ma et al, 18 Lorvand et al, 19 and Jiang 20 are among the researchers who investigated different aspects of δ − shock model. Models considering combination of above failure models for the systems are also proposed in the literature.…”