The management of defect tracking is one of important part of testing. The objective of test aims to find out the defect of software system. Therefore, the management of tracking defect, regarded as a vital part in the test, ensuring every observed defect immediately coped with. The paper discusses the objective of software defect management, the definition of defect ranking, the process of tracking defect management, and illustrates it with combining the Lotus Notes/Domino localized defect management.

Based on the analysis of six kinds of working points, the process function of torpedo thermal power propulsion system is solved. The results show that the process transfer function is approximate to inertial link. PI control algorithm is presented and its parameters are deduced. The algorithm can not only control the output variables, but also can monitor the intermediate variable. Closed-loop control system model is established. Variable speed characteristics of torpedo at constant depth and steady speed characteristics in depth-changed process are simulated by MATLAB. Simulation results indicate that the system has satisfactory dynamic performance and the control quality performs well.