Before revision:  In contrast to the original isotropic dual-front model, the use of the asymmetric enhancement can reduce the risk of shortcuts or leakage problems especially when the initial curves are far away from the target boundaries  .
After revision:  In contrast to the original isotropic dual-front model, the use of the asymmetric enhancement can reduce the risk of contour shortcut or leakage problems especially when the initial curves are far away from the target boundaries .