An optimized test sequence satisfying the completeness criteria

We present a problem of commonly used characterization sequences and propose a new test sequence to resolve the problem. The proposed test sequence could decide whether the output fault arises in the edge being tested or one of edges in the UIO sequence. Additionally, the fault coverage is much wider than other test sequence generation methods. To achieve the goal, we introduce k-strong FSM, and show that it can be constructed from a characterization sequence. Also, we show that the length of the test sequence satisfying the completeness can be reduced. Finally, we illustrate our technique on a specific example.