Concept Drift Visualization of SVM with Shifting Window

TL;DR

This paper introduces a novel visualization method using parallel histograms through time to detect and explain concept drift in data, especially for multidimensional datasets, with applications to SVM models.

Contribution

The paper presents a new visualization model based on parallel histograms through time for detecting and explaining concept drift in machine learning data.

Findings

Effective detection of concept drift in synthetic and real datasets

Visualization helps explain the decision changes in SVM models

Method reduces within-window drift, highlighting drift points

Abstract

In machine learning, concept drift is an evolution of information that invalidates the current data model. It happens when the statistical properties of the input data change over time in unforeseen ways. Concept drift detection is crucial when dealing with dynamically changing data. Its visualization can bring valuable insight into the data dynamics, especially for multidimensional data, and is related to visual knowledge discovery. We propose a novel visualization model based on parallel coordinates, denoted as parallel histograms through time. Our model represents histograms of feature distributions for successive time-shifted windows. The drift is shown as variations of these histograms, obtained by connecting the means of the distribution for successive time windows. We show how these diagrams can be used to explain the decision made by the machine learning model in choosing the drift point. By isolating the drift at the edges of successive time windows, there will be none (or reduced) drift within the adjacent windows. We illustrate this concept on both synthetic and real datasets. In our experiments, we use an incremental/decremental SVM with shifting window, introduced by us in previous work. With our proposed technique, in addition to detect the presence of concept drift, we can also depict it. This information can be further used to explain the change. mental results, opening the possibility for further investigations.