Cleansing Noisy Data Streams

In this paper, we identify a new research problem on cleansing noisy data streams which contain incorrectly labeled training examples. The objective is to accurately identify and remove mislabeled data, such that the prediction models built from the cleansed streams can be more accurate than the ones trained from the raw noisy streams. For this purpose, we first use bias-variance decomposition to derive a maximum variance margin (MVM) principle for stream data cleansing. Following this principle, we further propose a local and global filtering (LgF) framework to combine the strength of local noise filtering (within one single data chunk) and global noise filtering (across a number of adjacent data chunks) to identify erroneous data. Experimental results on six data streams (including two real-world data streams) demonstrate that LgF significantly outperforms simple methods in identifying noisy examples.