Piecewise Linear Approximation in Data Streaming: Algorithmic Implementations and Experimental Analysis.

Piecewise Linear Approximation (PLA) is a well-established tool to reduce the size of the representation of time series by approximating the series by a sequence of line segments while keeping the error introduced by the approximation within some predetermined threshold. With the recent rise of edge computing, PLA algorithms find a complete new set of applications with the emphasis on reducing the volume of streamed data. In this study, we identify two scenarios set in a data-stream processing context: data reduction in sensor transmissions and datacenter storage. In connection to those scenarios, we identify several streaming metrics and propose streaming protocols as algorithmic implementations of the state of the art PLA techniques. In an experimental evaluation, we measure the quality of the reviewed meth- ods and protocols and evaluate their performance against those streaming statistics. All known methods have defi- ciencies when it comes to handling streaming-like data, e.g. inflation of the input stream, high latency or poor aver- age error. Our experimental results highlight the challenges raised when transferring those classical methods into the stream processing world and present alternative techniques to overcome them and balance the related trade-offs.