How to quantify the impact of lossy transformations on change detection

Abstract

To ease the proliferation of big data, it frequently is transformed, be it by compression, be it by anonymization. Such transformations however modify characteristics of the data, such as changes in the case of time series. Changes however are important for subsequent analyses. The impact of those modifications depends on the application scenario, and quantifying it is far from trivial. This is because a transformation can shift or modify existing changes or introduce new ones. In this paper, we propose MILTON, a flexible and robust Measure for quantifying the Impact of Lossy Transformations on subsequent change detectiON. MILTON is applicable to any lossy transformation technique on time-series data and to any general-purpose change-detection approach. We have evaluated it with three real-world use cases. Our evaluation shows that MILTON allows to quantify the impact of lossy transformations and to choose the best one from a class of transformation techniques for a given application scenario.