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Yuming Yang

7 accepted papers

2025

Analyzing the Effects of Supervised Fine-Tuning on Model Knowledge from Token and Parameter Levels

EMNLP 2025

Large language models (LLMs) acquire substantial world knowledge during pre-training, which is further shaped by post-training techniques such as supervised fine-tuning (SFT). However, the impact of SFT on a model’s knowledge remains underexplored, limiting our ability to control knowledge behavior

Cited by 0SourcePDFScholar
2025

Beyond Boundaries: Learning a Universal Entity Taxonomy across Datasets and Languages for Open Named Entity Recognition

COLING 2025main

Open Named Entity Recognition (NER), which involves identifying arbitrary types of entities from arbitrary domains, remains challenging for Large Language Models (LLMs). Recent studies suggest that fine-tuning LLMs on extensive NER data can boost their performance. However, training directly on exis…

2025

Have the VLMs Lost Confidence? A Study of Sycophancy in VLMs

ICLR 2025poster

In the study of LLMs, sycophancy represents a prevalent hallucination that poses significant challenges to these models. Specifically, LLMs often fail to adhere to original correct responses, instead blindly agreeing with users' opinions, even when those opinions are incorrect or malicious. However,…

Cited by 0SourcePDFScholar
2025

Measuring Data Diversity for Instruction Tuning: A Systematic Analysis and A Reliable Metric

ACL 2025long

Data diversity is crucial for the instruction tuning of large language models. Existing studies have explored various diversity-aware data selection methods to construct high-quality datasets and enhance model performance. However, the fundamental problem of precisely defining and measuring data div…

2025

Mitigating Object Hallucinations in MLLMs via Multi-Frequency Perturbations

EMNLP 2025

Recently, multimodal large language models (MLLMs) have demonstrated remarkable performance in visual-language tasks. However, the authenticity of the responses generated by MLLMs is often compromised by object hallucinations. We identify that a key cause of these hallucinations is the model’s over-

Cited by 0SourcePDFScholar
2025

Pre-Trained Policy Discriminators are General Reward Models

NeurIPS 2025poster

We offer a novel perspective on reward modeling by formulating it as a policy discriminator, which quantifies the difference between two policies to generate a reward signal, guiding the training policy towards a target policy with desired behaviors. Based on this conceptual insight, we propose a sc…

Cited by 0SourceScholar
2025

TL-Training: A Task-Feature-Based Framework for Training Large Language Models in Tool Use

EMNLP 2025

Large language models (LLMs) achieve remarkable advancements by leveraging tools to interact with environments, a critical step toward generalized AI. However, the standard supervised fine-tuning (SFT) approach, which relies on large-scale datasets, often overlooks task-specific characteristics in t