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Guhao Feng

11 accepted papers

2026

Efficient Reasoning for Large Reasoning Language Models via Certainty-Guided Reflection Suppression

AAAI 2026technical

Recent Large Reasoning Language Models (LRLMs) employ long chain-of-thought reasoning with complex reflection behaviors, typically signaled by specific trigger words (e.g., "Wait" and "Alternatively") to enhance performance. However, these reflection behaviors can lead to the overthinking problem wh

Cited by 0SourcePDFScholar
2025

Beyond Online Sampling: Bridging Offline-to-Online Alignment via Dynamic Data Transformation for LLMs

EMNLP 2025

While Direct Preference Optimization (DPO) eliminates complex reward modeling in aligning large language models (LLMs) with human preferences, its online variant faces significant efficiency bottlenecks due to costly real-time preference sampling and the reward model annotation. We propose a novel f

2025

DPO Meets PPO: Reinforced Token Optimization for RLHF

ICML 2025spotlight

In the classical Reinforcement Learning from Human Feedback (RLHF) framework, Proximal Policy Optimization (PPO) is employed to learn from sparse, sentence-level rewards---a challenging scenario in traditional deep reinforcement learning. Despite the great successes of PPO in the alignment of state-…

2025

How Numerical Precision Affects Arithmetical Reasoning Capabilities of LLMs

ACL 2025finding

Despite the remarkable success of transformer-based large language models (LLMs) across various domains, understanding and enhancing their mathematical capabilities remains a significant challenge. In this paper, we conduct a rigorous theoretical analysis of LLMs’ mathematical abilities, with a spec…

Cited by 0SourcePDFScholar
2025

Theoretical Benefit and Limitation of Diffusion Language Model

NeurIPS 2025poster

Diffusion language models have emerged as a new approach for text generation. By enabling the parallel sampling of multiple tokens in each diffusion step, they appear to offer a more efficient alternative to auto-regressive models. However, our observations show that current open-sourced diffusion l…

Cited by 0SourceScholar
2024

Do Efficient Transformers Really Save Computation?

ICML 2024poster

As transformer-based language models are trained on increasingly large datasets and with vast numbers of parameters, finding more efficient alternatives to the standard Transformer has become very valuable. While many efficient Transformers and Transformer alternatives have been proposed, none provi…

Cited by 16SourcePDFScholar
2024

Rethinking Model-based, Policy-based, and Value-based Reinforcement Learning via the Lens of Representation Complexity

NeurIPS 2024poster

Reinforcement Learning (RL) encompasses diverse paradigms, including model-based RL, policy-based RL, and value-based RL, each tailored to approximate the model, optimal policy, and optimal value function, respectively. This work investigates the potential hierarchy of representation complexity amon…

2024

Two Stones Hit One Bird: Bilevel Positional Encoding for Better Length Extrapolation

ICML 2024poster

In this work, we leverage the intrinsic segmentation of language sequences and design a new positional encoding method called Bilevel Positional Encoding (BiPE). For each position, our BiPE blends an intra-segment encoding and an inter-segment encoding. The intra-segment encoding identifies the loca…

2023

A Complete Expressiveness Hierarchy for Subgraph GNNs via Subgraph Weisfeiler-Lehman Tests

ICML 2023poster

Recently, subgraph GNNs have emerged as an important direction for developing expressive graph neural networks (GNNs). While numerous architectures have been proposed, so far there is still a limited understanding of how various design paradigms differ in terms of expressive power, nor is it clear w…

2023

Towards Revealing the Mystery behind Chain of Thought: A Theoretical Perspective

NeurIPS 2023oral

Recent studies have discovered that Chain-of-Thought prompting (CoT) can dramatically improve the performance of Large Language Models (LLMs), particularly when dealing with complex tasks involving mathematics or reasoning. Despite the enormous empirical success, the underlying mechanisms behind CoT…

Cited by 247SourcePDFScholar