Göpfert, Jan Philip
Explainable Artificial Intelligence for Improved Modeling of Processes
Velioglu, Riza, Göpfert, Jan Philip, Artelt, André, Hammer, Barbara
In modern business processes, the amount of data collected has increased substantially in recent years. Because this data can potentially yield valuable insights, automated knowledge extraction based on process mining has been proposed, among other techniques, to provide users with intuitive access to the information contained therein. At present, the majority of technologies aim to reconstruct explicit business process models. These are directly interpretable but limited concerning the integration of diverse and real-valued information sources. On the other hand, Machine Learning (ML) benefits from the vast amount of data available and can deal with high-dimensional sources, yet it has rarely been applied to being used in processes. In this contribution, we evaluate the capability of modern Transformer architectures as well as more classical ML technologies of modeling process regularities, as can be quantitatively evaluated by their prediction capability. In addition, we demonstrate the capability of attentional properties and feature relevance determination by highlighting features that are crucial to the processes' predictive abilities. We demonstrate the efficacy of our approach using five benchmark datasets and show that the ML models are capable of predicting critical outcomes and that the attention mechanisms or XAI components offer new insights into the underlying processes.
Locally Adaptive Nearest Neighbors
Göpfert, Jan Philip, Wersing, Heiko, Hammer, Barbara
When training automated systems, it has been shown to be beneficial to adapt the representation of data by learning a problem-specific metric. We extend this idea and, for the widely used family of k nearest neighbors algorithms, develop a method that allows learning locally adaptive metrics. To demonstrate important aspects of how our approach works, we conduct a number of experiments on synthetic data sets, and we show its usefulness on real-world benchmark data sets. Machine learning models increasingly pervade our daily lives in the form of recommendation systems, computer vision, driver assistance, etc., challenging us to realize seamless cooperation between human and algorithmic agents. One desirable property of predictions made by machine learning models is their transparency, expressed in such a way as a statement about which factors of a given setting have the greatest influence on the decision at hand - in particular, this requirement aligns with the EU General Data Protection Regulations, which include a "right to explanation" [1].
Adversarial Robustness Curves
Göpfert, Christina, Göpfert, Jan Philip, Hammer, Barbara
The existence of adversarial examples has led to considerable uncertainty regarding the trust one can justifiably put in predictions produced by automated systems. This uncertainty has, in turn, lead to considerable research effort in understanding adversarial robustness. In this work, we take first steps towards separating robustness analysis from the choice of robustness threshold and norm. We propose robustness curves as a more general view of the robustness behavior of a model and investigate under which circumstances they can qualitatively depend on the chosen norm.
Adversarial attacks hidden in plain sight
Göpfert, Jan Philip, Wersing, Heiko, Hammer, Barbara
The use of convolutional neural networks has led to tremendous achievements since Krizhevsky et al. [1] presented AlexNet in 2012. Despite efforts to understand the inner workings of such neural networks, they mostly remain black boxes that are hard to interpret or explain. The issue was exaggerated in 2013 when Szegedy et al. [2] showed that "adversarial examples" - images perturbed in such a way that they fool a neural network - prove that neural networks do not simply work correctly the way one might naïvely expect. Typically,such adversarial attacks change an input only slightly, but in an adversarial manner, such that humans would not regard the difference of the inputs relevant, but machines do. There are various types of attacks, such as one pixel attacks, attacks that work in the physical world, and attacks that produce inputs fooling several different neural networks without explicit knowledge of those networks [3, 4, 5].