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Jannik Kossen

11 accepted papers

2025

Rethinking Aleatoric and Epistemic Uncertainty

ICML 2025poster

The ideas of aleatoric and epistemic uncertainty are widely used to reason about the probabilistic predictions of machine-learning models. We identify incoherence in existing discussions of these ideas and suggest this stems from the aleatoric-epistemic view being insufficiently expressive to captur…

Cited by 2SourcePDFScholar
2025

Scaling Up Active Testing to Large Language Models

NeurIPS 2025poster

Active testing enables label-efficient evaluation of predictive models through careful data acquisition, but it can pose a significant computational cost. We identify cost-saving measures that enable active testing to be scaled up to large language models (LLMs). In particular we show that the surro…

Cited by 0SourceScholar
2025

Simple Factuality Probes Detect Hallucinations in Long-Form Natural Language Generation

EMNLP 2025

Large language models (LLMs) often mislead users with confident hallucinations. Current approaches to detect hallucination require many samples from the LLM generator, which is computationally infeasible as frontier model sizes and generation lengths continue to grow. We present a remarkably simple

2024

Estimating the Hallucination Rate of Generative AI

NeurIPS 2024poster

This paper presents a method for estimating the hallucination rate for in-context learning (ICL) with generative AI. In ICL, a conditional generative model (CGM) is prompted with a dataset and a prediction question and asked to generate a response. One interpretation of ICL assumes that the CGM comp…

Cited by 6SourcePDFScholar
2024

In-Context Learning Learns Label Relationships but Is Not Conventional Learning

ICLR 2024poster

The predictions of Large Language Models (LLMs) on downstream tasks often improve significantly when including examples of the input–label relationship in the context. However, there is currently no consensus about how this in-context learning (ICL) ability of LLMs works. For example, while Xie et a…

2024

Kernel Language Entropy: Fine-grained Uncertainty Quantification for LLMs from Semantic Similarities

NeurIPS 2024poster

Uncertainty quantification in Large Language Models (LLMs) is crucial for applications where safety and reliability are important. In particular, uncertainty can be used to improve the trustworthiness of LLMs by detecting factually incorrect model responses, commonly called hallucinations. Criticall…

2023

Three Towers: Flexible Contrastive Learning with Pretrained Image Models

NeurIPS 2023poster

We introduce Three Towers (3T), a flexible method to improve the contrastive learning of vision-language models by incorporating pretrained image classifiers. While contrastive models are usually trained from scratch, LiT (Zhai et al., 2022) has recently shown performance gains from using pretrained…

2022

Active Surrogate Estimators: An Active Learning Approach to Label-Efficient Model Evaluation

NeurIPS 2022accept

We propose Active Surrogate Estimators (ASEs), a new method for label-efficient model evaluation. Evaluating model performance is a challenging and important problem when labels are expensive. ASEs address this active testing problem using a surrogate-based estimation approach that interpolates the…

2021

Active Testing: Sample-Efficient Model Evaluation

ICML 2021spotlight

We introduce a new framework for sample-efficient model evaluation that we call active testing. While approaches like active learning reduce the number of labels needed for model training, existing literature largely ignores the cost of labeling test data, typically unrealistically assuming large te…

2021

Self-Attention Between Datapoints: Going Beyond Individual Input-Output Pairs in Deep Learning

NeurIPS 2021poster

We challenge a common assumption underlying most supervised deep learning: that a model makes a prediction depending only on its parameters and the features of a single input. To this end, we introduce a general-purpose deep learning architecture that takes as input the entire dataset instead of pro…

2020

Structured Object-Aware Physics Prediction for Video Modeling and Planning

ICLR 2020poster

When humans observe a physical system, they can easily locate components, understand their interactions, and anticipate future behavior, even in settings with complicated and previously unseen interactions. For computers, however, learning such models from videos in an unsupervised fashion is an uns…

Cited by 73SourcecodeScholar