A Data-driven Approach to Detecting Change Points in High Concentration of Outliers and Autocorrelated Noise
摘要
Change point detection in sequential data becomes substantially more challenging when datasets exhibit both autocorrelated noise and a high concentration of transient outliers. We present a two-phase framework that first detects candidate change points using the DeCAFS algorithm under an AR(1) noise model, and then classifies each detection as a sustained structural shift or a recoiled transient outlier using a Fourier Probabilistic Neural Network (FPNN). The framework incorporates three methodological contributions beyond the base DeCAFS detector: (i) a Bayesian Online Change Point Detector (BOCPD) used as a labelling oracle during training to produce principled sustained/recoiled annotations; (ii) a local Extreme Value Index estimated via Generalized Pareto Distribution fitting, introduced as a fifth classification feature encoding tail behaviour; and (iii) a class-weighted FPNN with SMOTE-balanced training, evaluated under balanced accuracy, Matthews Correlation Coefficient, and other robust metrics. The framework is evaluated on three datasets: the