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Jens Lehmann

24 accepted papers

2026

Advancing Safe Mechanical Ventilation Using Offline RL with Hybrid Actions and Clinically Aligned Rewards

AAAI 2026technical

Invasive mechanical ventilation (MV) is a life-sustaining therapy commonly used in the intensive care unit (ICU) for patients with severe and acute conditions. These patients frequently rely on MV for breathing. Given the high risk of death in such cases, optimal MV settings can reduce mortality, mi

Cited by 0SourcePDFScholar
2024

Enhancing Contextual Understanding in Large Language Models through Contrastive Decoding

NAACL 2024long

Large language models (LLMs) tend to inadequately integrate input context during text generation, relying excessively on encoded prior knowledge in model parameters, potentially resulting in generated text with factual inconsistencies or contextually unfaithful content. LLMs utilize two primary know…

2024

Investigating Multilingual Instruction-Tuning: Do Polyglot Models Demand for Multilingual Instructions?

EMNLP 2024main

The adaption of multilingual pre-trained LLMs into eloquent and helpful assistants is essential to facilitate their use across different language regions. In that spirit, we are the first to conduct an extensive study of the performance of multilingual models instruction-tuned on different language…

2024

Knowledge GeoGebra: Leveraging Geometry of Relation Embeddings in Knowledge Graph Completion

COLING 2024main

Knowledge graph embedding (KGE) models provide a low-dimensional representation of knowledge graphs in continuous vector spaces. This representation learning enables different downstream AI tasks such as link prediction for graph completion. However, most embedding models are only designed consideri…

2024

MATTER: Memory-Augmented Transformer Using Heterogeneous Knowledge Sources

ACL 2024findings

Leveraging external knowledge is crucial for achieving high performance in knowledge-intensive tasks, such as question answering. The retrieve-and-read approach is widely adopted for integrating external knowledge into a language model. However, this approach suffers from increased computational cos…

Cited by 1SourcePDFScholar
2024

REXEL: An End-to-end Model for Document-Level Relation Extraction and Entity Linking

NAACL 2024industry

Extracting structured information from unstructured text is critical for many downstream NLP applications and is traditionally achieved by closed information extraction (cIE). However, existing approaches for cIE suffer from two limitations: (i) they are often pipelines which makes them prone to err…

2023

Direct Fact Retrieval from Knowledge Graphs without Entity Linking

ACL 2023long

There has been a surge of interest in utilizing Knowledge Graphs (KGs) for various natural language processing/understanding tasks. The conventional mechanism to retrieve facts in KGs usually involves three steps: entity span detection, entity disambiguation, and relation classification. However, th…

2023

INVITE: a Testbed of Automatically Generated Invalid Questions to Evaluate Large Language Models for Hallucinations

EMNLP 2023short findings

Recent advancements in Large language models (LLMs) have enabled them to hold free form conversations over multiple turns, but they exhibit a tendency to make unfounded and incorrect statements, commonly known as hallucinations. In particular, LLMs hallucinate frequently when given invalid question…

Cited by 0SourceScholar
2023

Knowledge Graph Embeddings using Neural Ito Process: From Multiple Walks to Stochastic Trajectories

ACL 2023findings

Knowledge graphs mostly exhibit a mixture of branching relations, e.g., hasFriend, and complex structures, e.g., hierarchy and loop. Most knowledge graph embeddings have problems expressing them, because they model a specific relation r from a head h to tails by starting at the node embedding of h a…

2023

mReFinED: An Efficient End-to-End Multilingual Entity Linking System

EMNLP 2023short findings

End-to-end multilingual entity linking (MEL) is concerned with identifying multilingual entity mentions and their corresponding entity IDs in a knowledge base. Existing works assumed that entity mentions were given and skipped the entity mention detection step due to a lack of high-quality multiling…

Cited by 0SourceScholar
2022

Climate Bot: A Machine Reading Comprehension System for Climate Change Question Answering

IJCAI 2022poster

Climate change has a severe impact on the overall ecosystem of the whole world, including humankind. This demo paper presents Climate Bot - a machine reading comprehension system for question answering over documents about climate change. The proposed Climate Bot provides an interface for users to a…

2022

DialoKG: Knowledge-Structure Aware Task-Oriented Dialogue Generation

NAACL 2022findings

Task-oriented dialogue generation is challenging since the underlying knowledge is often dynamic and effectively incorporating knowledge into the learning process is hard. It is particularly challenging to generate both human-like and informative responses in this setting. Recent research primarily…

2022

Improving Inductive Link Prediction Using Hyper-Relational Facts (Extended Abstract)

IJCAI 2022poster

For many years, link prediction on knowledge. graphs has been a purely transductive task, not allowing for reasoning on unseen entities. Recently, increasing efforts are put into exploring semi- and fully inductive scenarios, enabling inference over unseen and emerging entities. Still, all these…

2022

RoMe: A Robust Metric for Evaluating Natural Language Generation

ACL 2022long

Evaluating Natural Language Generation (NLG) systems is a challenging task. Firstly, the metric should ensure that the generated hypothesis reflects the reference’s semantics. Secondly, it should consider the grammatical quality of the generated sentence. Thirdly, it should be robust enough to handl…

2021

5* Knowledge Graph Embeddings with Projective Transformations

AAAI 2021technical

Performing link prediction using knowledge graph embedding models has become a popular approach for knowledge graph completion. Such models employ a transformation function that maps nodes via edges into a vector space in order to measure the likelihood of the links. While mapping the individual nod…

Cited by 41SourcePDFScholar
2021

Knowledge Graph Representation Learning using Ordinary Differential Equations

EMNLP 2021main

Knowledge Graph Embeddings (KGEs) have shown promising performance on link prediction tasks by mapping the entities and relations from a knowledge graph into a geometric space. The capability of KGEs in preserving graph characteristics including structural aspects and semantics, highly depends on th…

2021

Proxy Indicators for the Quality of Open-domain Dialogues

EMNLP 2021main

The automatic evaluation of open-domain dialogues remains a largely unsolved challenge. Despite the abundance of work done in the field, human judges have to evaluate dialogues’ quality. As a consequence, performing such evaluations at scale is usually expensive. This work investigates using a deep-…

2021

Relational Pattern Benchmarking on the Knowledge Graph Link Prediction Task

NeurIPS 2021poster

Knowledge graphs (KGs) encode facts about the world in a graph data structure where entities, represented as nodes, connect via relationships, acting as edges. KGs are widely used in Machine Learning, e.g., to solve Natural Language Processing based tasks. Despite all the advancements in KGs, they p…

Cited by 9SourceScholar
2021

Space Efficient Context Encoding for Non-Task-Oriented Dialogue Generation with Graph Attention Transformer

ACL 2021long

To improve the coherence and knowledge retrieval capabilities of non-task-oriented dialogue systems, recent Transformer-based models aim to integrate fixed background context. This often comes in the form of knowledge graphs, and the integration is done by creating pseudo utterances through paraphra…

2021

Temporal Knowledge Graph Completion using a Linear Temporal Regularizer and Multivector Embeddings

NAACL 2021long

Representation learning approaches for knowledge graphs have been mostly designed for static data. However, many knowledge graphs involve evolving data, e.g., the fact (The President of the United States is Barack Obama) is valid only from 2009 to 2017. This introduces important challenges for knowl…

2021

Time-aware Graph Neural Network for Entity Alignment between Temporal Knowledge Graphs

EMNLP 2021main

Entity alignment aims to identify equivalent entity pairs between different knowledge graphs (KGs). Recently, the availability of temporal KGs (TKGs) that contain time information created the need for reasoning over time in such TKGs. Existing embedding-based entity alignment approaches disregard ti…

2020

Knowledge Graph Embeddings in Geometric Algebras

COLING 2020main

Knowledge graph (KG) embedding aims at embedding entities and relations in a KG into a low dimensional latent representation space. Existing KG embedding approaches model entities and relations in a KG by utilizing real-valued , complex-valued, or hypercomplex-valued (Quaternion or Octonion) represe…

2020

Language Model Transformers as Evaluators for Open-domain Dialogues

COLING 2020main

Computer-based systems for communication with humans are a cornerstone of AI research since the 1950s. So far, the most effective way to assess the quality of the dialogues produced by these systems is to use resource-intensive manual labor instead of automated means. In this work, we investigate wh…

2020

TeRo: A Time-aware Knowledge Graph Embedding via Temporal Rotation

COLING 2020main

In the last few years, there has been a surge of interest in learning representations of entities and relations in knowledge graph (KG). However, the recent availability of temporal knowledge graphs (TKGs) that contain time information for each fact created the need for reasoning over time in such T…