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Christian Bartelt

11 accepted papers

2025

DCBM: Data-Efficient Visual Concept Bottleneck Models

ICML 2025poster

Concept Bottleneck Models (CBMs) enhance the interpretability of neural networks by basing predictions on human-understandable concepts. However, current CBMs typically rely on concept sets extracted from large language models or extensive image corpora, limiting their effectiveness in data-sparse s…

2025

Large Language Models Share Representations of Latent Grammatical Concepts Across Typologically Diverse Languages

NAACL 2025long

Human bilinguals often use similar brain regions to process multiple languages, depending on when they learned their second language and their proficiency. In large language models (LLMs), how are multiple languages learned and encoded? In this work, we explore the extent to which LLMs share represe…

2025

Mitigating Information Loss in Tree-Based Reinforcement Learning via Direct Optimization

ICLR 2025spotlight

Reinforcement learning (RL) has seen significant success across various domains, but its adoption is often limited by the black-box nature of neural network policies, making them difficult to interpret. In contrast, symbolic policies allow representing decision-making strategies in a compact and int…

2024

A Data-Centric Perspective on Evaluating Machine Learning Models for Tabular Data

NeurIPS 2024poster

Tabular data is prevalent in real-world machine learning applications, and new models for supervised learning of tabular data are frequently proposed. Comparative studies assessing performance differences typically have model-centered evaluation setups with overly standardized data preprocessing. Th…

2024

A Mechanistic Analysis of a Transformer Trained on a Symbolic Multi-Step Reasoning Task

ACL 2024findings

Transformers demonstrate impressive performance on a range of reasoning benchmarks. To evaluate the degree to which these abilities are a result of actual reasoning, existing work has focused on developing sophisticated benchmarks for behavioral studies. However, these studies do not provide insight…

2024

Enabling Mixed Effects Neural Networks for Diverse, Clustered Data Using Monte Carlo Methods

IJCAI 2024poster

Neural networks often assume independence among input data samples, disregarding correlations arising from inherent clustering patterns in real-world datasets (e.g., due to different sites or repeated measurements). Recently, mixed effects neural networks (MENNs) which separate cluster-specific 'ran…

2024

GRANDE: Gradient-Based Decision Tree Ensembles for Tabular Data

ICLR 2024poster

Despite the success of deep learning for text and image data, tree-based ensemble models are still state-of-the-art for machine learning with heterogeneous tabular data. However, there is a significant need for tabular-specific gradient-based methods due to their high flexibility. In this paper, we…

2024

GradTree: Learning Axis-Aligned Decision Trees with Gradient Descent

AAAI 2024technical

Decision Trees (DTs) are commonly used for many machine learning tasks due to their high degree of interpretability. However, learning a DT from data is a difficult optimization problem, as it is non-convex and non-differentiable. Therefore, common approaches learn DTs using a greedy growth algorith…

2023

A Multidimensional Analysis of Social Biases in Vision Transformers

ICCV 2023poster

The embedding spaces of image models have been shown to encode a range of social biases such as racism and sexism. Here, we investigate specific factors that contribute to the emergence of these biases in Vision Transformers (ViT). Therefore, we measure the impact of training data, model architectur…

Cited by 10PDFcodeScholar
2023

Online Random Feature Forests for Learning in Varying Feature Spaces

AAAI 2023technical

In this paper, we propose a new online learning algorithm tailored for data streams described by varying feature spaces (VFS), wherein new features constantly emerge and old features may stop to be observed over various time spans. Our proposed algorithm, named Online Random Feature Forests for Feat…

Cited by 14SourcePDFScholar