Distributionally Robust Fault Detection by using Kernel Density Estimation⁎This work was supported in part by the National Natural Science Foundation of China under Grants (61873149 and 61733009), the Research Fund for the Taishan Scholar Project of Shandong Province of China, the Beijing Natural Science Foundation under grant 4202045, and the Fundamental Research Funds for the Central Universities under Grant FRF-TP-19-032A2. Issue 2 (2020)