Daniel Dahlmeier

Author directory

2026

Large Language Models (LLMs) excel when a solution can be planned from the prompt, but many sequential decision-making tasks require actions to depend on observations acquired during interaction. We study two central challenges in this regime: learning reusable interaction policies for history-dependent search, and acting under partial observability when task-relevant state is revealed only through interaction. We instantiate these challenges with two diagnostic benchmarks: Calc-Bench for reusable, history-dependent tool interaction, and partially observed sorting for action selection under hidden state. We introduce the Expanded Action space (ExpA), which decouples language reasoning from environment interaction by adding routing and environment-specific actions beyond vocabulary tokens. ExpA is trained with EARL, an RL algorithm using counterfactual policy optimization to explore rarely invoked but useful actions. EARL improves Countdown by 26.3% with 3B models and achieves perfect Sort-4 accuracy while discovering an efficient sorting strategy, providing a proof-of-concept for learned non-language interaction in controlled sequential decision-making diagnostics.
Whether attention weights faithfully reflect model reasoning has been actively debated in NLP, yet this question remains largely unexplored for the visual modality in Vision-Language Models (VLMs). We address this gap through causal perturbation analysis on current VLMs, evaluating both the comprehensiveness and sufficiency gap of attention-ranked visual tokens. Our analysis reveals that visual attention faithfulness is heterogeneous, manifesting in three distinct processing modes: *Faithful-Sufficient*, where top-k attention tokens are both necessary and sufficient for prediction; *Faithful-Distributed*, where they are necessary but broader visual context remains required; and *Non-Focal*, where no localized attention region is individually necessary while visual information remains an essential trigger for prediction. Furthermore, human-annotated ground-truth regions satisfy comprehensiveness in only ∼60% of cases compared with model attention rankings, revealing systematic divergence between model visual reliance and human intuition. We demonstrate these patterns across both general VQA on VQAv2 and document tasks on VRDU and ChartQA, showing that visual attention faithfulness varies systematically with processing demands and model architectures rather than being uniformly faithful or unfaithful.
In enterprise applications, document information extraction (IE) does not operate in isolation: extracted information must match the systems of record (SoR) for the process to work. While reliable IE demands entity extraction, SoR grounding, and iterative refinement, existing methods rely on single-pass inference. To address this gap, we propose a SoR-grounded agentic pipeline and evaluate four agentic paradigms (Agentic Workflow, ReAct, Plan-Execute-Critic, and Dynamic Agent Collaboration) on real-world enterprise data. We focus on the goods receipt and invoice settlement processes as representative use cases, where delivery notes and invoices must be matched and verified against purchase order SoR. Our results show that agentic approaches generally match or exceed non-agentic baselines, with simpler paradigms matching or outperforming complex alternatives. Paired with systematic error analysis, this work provides actionable guidance for deploying agentic document AI at enterprise scale.
Vision Language Model (VLM)-based OCR-free pipelines are increasingly adopted for industrial Key Information Extraction (KIE) systems due to their simpler end-to-end architecture and reduced dependence on potentially noisy OCR outputs. However, their reliability in grounding extracted values to precise bounding boxes remains unclear, raising questions about their suitability for grounding-critical use cases. In this paper, we present a systematic study of bounding box grounding capability in both general and document-specific VLMs. Our findings reveal a consistent extraction-grounding gap across model families. We revisit the OCR system as a grounding primitive and find that delegating the grounding step to Large Language Models (LLMs), rather than VLMs, in a zero-shot manner substantially improves region-level grounding accuracy. We introduce a fine-tuned 0.6B LLM that further improves the predicted box alignment, achieving high overlap with the target field for in-domain data while maintaining low serving latency. These results position OCR-anchored grounding as a practical deployment choice for industrial KIE systems that require both extraction and precise localization.
Document understanding requires modeling both structural and semantic relationships between the layout elements within the document, with human-perceived reading order (RO) playing a crucial yet often neglected role compared to heuristic OCR sequences used by most existing models. Previous approaches depend on costly, inconsistent human annotations, limiting scalability and generalization. To bridge the gap, we propose a cost-effective paradigm that leverages large language models (LLMs) to infer global RO and inter-element layout relations without human supervision. By explicitly incorporating RO as structural guidance, our method captures hierarchical, document-level dependencies beyond local adjacency. Experiments on Semantic Entity Recognition, Entity Linking, and Document Question Answering show consistent improvements over baseline methods. Notably, LLM-inferred RO, even when differing from ground-truth adjacency, provides richer global structural priors and yields superior downstream performance. These results and findings demonstrate the scalability and significance of RO-aware modeling, advancing both LLMs and lightweight layout-aware models for robust document understanding. Code, data, and more details will be made publicly available after corporate review, in accordance with SAP’s corporate open-source policy.
Multimodal Large Language Models (MLLMs) enhance the potential of natural language processing. However, their actual impact on document information extraction remains unclear. In particular, it is unclear whether an MLLM-only pipeline—while simpler—can truly match the performance of traditional OCR+MLLM setups. In this paper, we conduct a large-scale benchmarking study that evaluates various out-of-the-box MLLMs on business-document information extraction. To examine and explore failure modes, we propose an automated hierarchical error analysis framework that leverages large language models (LLMs) to diagnose error patterns systematically. Our findings suggest that OCR may not be necessary for powerful MLLMs, as image-only input can achieve comparable performance to OCR-enhanced approaches. Moreover, we demonstrate that carefully designed schema, exemplars, and instructions can further enhance MLLMs performance. We hope this work can offer practical guidance and valuable insight for advancing document information extraction.
Despite the success of Large Language Models (LLMs) in structured query generation, OData—a critical RESTful protocol for enterprise APIs—remains under-researched due to a lack of high-fidelity, execution-validated datasets. To bridge this gap, we introduce OmniOData, a framework that generates SynOData, the first large-scale OData corpus featuring execution-grounded queries and reasoning traces. Using this corpus, we develop OmniOData-R1 (1.5B–3B parameters), a family of models that match or surpass frontier proprietary systems, such as GPT-4o and Gemini 3, on realistic industrial benchmarks. Our results demonstrate that the synergy of execution-verified synthetic data and Reinforcement Learning (RL) effectively unlocks the latent reasoning of Small Language Models (SLMs), providing a high-performance, low-latency solution for specialized enterprise query generation.The code and data will be released under an open-source license.

2025

Current Large Language Model (LLM) evaluation frameworks utilize the same static prompt template across all models under evaluation. This differs from the common industry practice of using prompt optimization (PO) techniques to optimize the prompt for each model to maximize application performance. In this paper, we investigate the effect of PO towards LLM evaluations. Our results on public academic and internal industry benchmarks show that PO greatly affects the final ranking of models. This highlights the importance of practitioners performing PO per model when conducting evaluations to choose the best model for a given task.

2023

2019

Aspect-based sentiment analysis produces a list of aspect terms and their corresponding sentiments for a natural language sentence. This task is usually done in a pipeline manner, with aspect term extraction performed first, followed by sentiment predictions toward the extracted aspect terms. While easier to develop, such an approach does not fully exploit joint information from the two subtasks and does not use all available sources of training information that might be helpful, such as document-level labeled sentiment corpus. In this paper, we propose an interactive multi-task learning network (IMN) which is able to jointly learn multiple related tasks simultaneously at both the token level as well as the document level. Unlike conventional multi-task learning methods that rely on learning common features for the different tasks, IMN introduces a message passing architecture where information is iteratively passed to different tasks through a shared set of latent variables. Experimental results demonstrate superior performance of the proposed method against multiple baselines on three benchmark datasets.

2018

Attention-based long short-term memory (LSTM) networks have proven to be useful in aspect-level sentiment classification. However, due to the difficulties in annotating aspect-level data, existing public datasets for this task are all relatively small, which largely limits the effectiveness of those neural models. In this paper, we explore two approaches that transfer knowledge from document-level data, which is much less expensive to obtain, to improve the performance of aspect-level sentiment classification. We demonstrate the effectiveness of our approaches on 4 public datasets from SemEval 2014, 2015, and 2016, and we show that attention-based LSTM benefits from document-level knowledge in multiple ways.
We consider the cross-domain sentiment classification problem, where a sentiment classifier is to be learned from a source domain and to be generalized to a target domain. Our approach explicitly minimizes the distance between the source and the target instances in an embedded feature space. With the difference between source and target minimized, we then exploit additional information from the target domain by consolidating the idea of semi-supervised learning, for which, we jointly employ two regularizations — entropy minimization and self-ensemble bootstrapping — to incorporate the unlabeled target data for classifier refinement. Our experimental results demonstrate that the proposed approach can better leverage unlabeled data from the target domain and achieve substantial improvements over baseline methods in various experimental settings.
Aspect-level sentiment classification aims to determine the sentiment polarity of a review sentence towards an opinion target. A sentence could contain multiple sentiment-target pairs; thus the main challenge of this task is to separate different opinion contexts for different targets. To this end, attention mechanism has played an important role in previous state-of-the-art neural models. The mechanism is able to capture the importance of each context word towards a target by modeling their semantic associations. We build upon this line of research and propose two novel approaches for improving the effectiveness of attention. First, we propose a method for target representation that better captures the semantic meaning of the opinion target. Second, we introduce an attention model that incorporates syntactic information into the attention mechanism. We experiment on attention-based LSTM (Long Short-Term Memory) models using the datasets from SemEval 2014, 2015, and 2016. The experimental results show that the conventional attention-based LSTM can be substantially improved by incorporating the two approaches.

2017

This paper highlights challenges in industrial research related to translating research in natural language processing into commercial products. While the interest in natural language processing from industry is significant, the transfer of research to commercial products is non-trivial and its challenges are often unknown to or underestimated by many researchers. I discuss current obstacles and provide suggestions for increasing the chances for translating research to commercial success based on my experience in industrial research.
Aspect extraction is an important and challenging task in aspect-based sentiment analysis. Existing works tend to apply variants of topic models on this task. While fairly successful, these methods usually do not produce highly coherent aspects. In this paper, we present a novel neural approach with the aim of discovering coherent aspects. The model improves coherence by exploiting the distribution of word co-occurrences through the use of neural word embeddings. Unlike topic models which typically assume independently generated words, word embedding models encourage words that appear in similar contexts to be located close to each other in the embedding space. In addition, we use an attention mechanism to de-emphasize irrelevant words during training, further improving the coherence of aspects. Experimental results on real-life datasets demonstrate that our approach discovers more meaningful and coherent aspects, and substantially outperforms baseline methods on several evaluation tasks.

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