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Yikun Ban

18 accepted papers

2026

Contextual Rollout Bandits for Reinforcement Learning with Verifiable Rewards

ICML 2026poster

Reinforcement Learning with Verifiable Rewards (RLVR) is an effective paradigm for improving the reasoning capabilities of large language models. However, existing RLVR methods utilize rollouts in an indiscriminate and short-horizon manner: responses of heterogeneous quality within each prompt are t…

Cited by 0SourceScholar
2026

Does Your Reasoning Model Implicitly Know When to Stop Thinking?

ICML 2026poster

Recent advancements in large reasoning models (LRMs) have greatly improved their capabilities on complex reasoning tasks through Long Chains of Thought (CoTs). However, this approach often results in substantial redundancy, impairing computational efficiency and causing significant delays in real-ti…

Cited by 0SourceScholar
2026

GCL-OT: Graph Contrastive Learning with Optimal Transport for Heterophilic Text-Attributed Graphs

AAAI 2026technical

Recently, structure–text contrastive learning has shown promising performance on text-attributed graphs by leveraging the complementary strengths of graph neural networks and language models. However, existing methods typically rely on homophily assumptions in similarity estimation and hard optimiza

Cited by 0SourcePDFScholar
2026

Harnessing Multiple Large Language Models: A Survey on LLM Ensemble

IJCAI 2026

LLM Ensemble---which involves the comprehensive use of multiple large language models (LLMs), each aimed at handling user queries during downstream inference, to benefit from their individual strengths---has gained substantial attention recently. The widespread availability of LLMs, coupled with the

Cited by 0Scholar
2026

Real-Time Aligned Reward Model beyond Semantics

ICML 2026poster

Reinforcement Learning from Human Feedback (RLHF) is a pivotal technique for aligning large language models (LLMs) with human preferences, yet it is susceptible to reward overoptimization, in which policy models overfit to the reward model, exploit spurious reward patterns instead of faithfully capt…

Cited by 0SourceScholar
2026

T-POP: Test-Time Personalization with Online Preference Feedback

ICML 2026poster

Personalizing large language models (LLMs) to individual user preferences is a critical step beyond generating generically helpful responses. However, current personalization methods are ill-suited for new users, as they typically require either slow, resource-intensive fine-tuning or a substantial …

Cited by 0SourceScholar
2025

Adaptive Batch-Wise Sample Scheduling for Direct Preference Optimization

NeurIPS 2025poster

Direct Preference Optimization (DPO) has emerged as an effective approach for aligning large language models (LLMs) with human preferences. However, its performance is highly dependent on the quality of the underlying human preference data. To address this bottleneck, prior work has explored various…

Cited by 0SourceScholar
2025

Can Graph Neural Networks Learn Language with Extremely Weak Text Supervision?

ACL 2025long

While great success has been achieved in building vision models with Contrastive Language-Image Pre-training (CLIP) over Internet-scale image-text pairs, building transferable Graph Neural Networks (GNNs) with CLIP pipeline is challenging because of the scarcity of labeled data and text supervision,…

2025

LLM-Forest: Ensemble Learning of LLMs with Graph-Augmented Prompts for Data Imputation

ACL 2025finding

Missing data imputation is a critical challenge in various domains, such as healthcare and finance, where data completeness is vital for accurate analysis. Large language models (LLMs), trained on vast corpora, have shown strong potential in data generation, making them a promising tool for data imp…

2025

Transformer Copilot: Learning from The Mistake Log in LLM Fine-tuning

NeurIPS 2025spotlight

Large language models are typically adapted to downstream tasks through supervised fine-tuning on domain-specific data. While standard fine-tuning focuses on minimizing generation loss to optimize model parameters, we take a deeper step by retaining and leveraging the model’s own learning signals, a…

Cited by 0SourcecodeScholar
2024

Contextual Bandits with Online Neural Regression

ICLR 2024poster

Recent works have shown a reduction from contextual bandits to online regression under a realizability assumption (Foster and Rakhlin, 2020; Foster and Krishnamurthy, 2021). In this work, we investigate the use of neural networks for such online regression and associated Neural Contextual Bandits (N…

Cited by 3SourcePDFScholar
2024

Neural Active Learning Beyond Bandits

ICLR 2024poster

We study both stream-based and pool-based active learning with neural network approximations. A recent line of works proposed bandit-based approaches that transformed active learning into a bandit problem, achieving both theoretical and empirical success. However, the performance and computational c…

Cited by 6SourcePDFScholar
2024

PageRank Bandits for Link Prediction

NeurIPS 2024poster

Link prediction is a critical problem in graph learning with broad applications such as recommender systems and knowledge graph completion. Numerous research efforts have been directed at solving this problem, including approaches based on similarity metrics and Graph Neural Networks (GNN). However,…

2024

Robust Neural Contextual Bandit against Adversarial Corruptions

NeurIPS 2024poster

Contextual bandit algorithms aim to identify the optimal arm with the highest reward among a set of candidates, based on the accessible contextual information. Among these algorithms, neural contextual bandit methods have shown generally superior performances against linear and kernel ones, due to t…

Cited by 0SourcePDFScholar
2023

Meta-Learning with Neural Bandit Scheduler

NeurIPS 2023poster

Meta-learning has been proven an effective learning paradigm for training machine learning models with good generalization ability. Apart from the common practice of uniformly sampling the meta-training tasks, existing methods working on task scheduling strategies are mainly based on pre-defined sam…

2022

EE-Net: Exploitation-Exploration Neural Networks in Contextual Bandits

ICLR 2022spotlight

In this paper, we propose a novel neural exploration strategy in contextual bandits, EE-Net, distinct from the standard UCB-based and TS-based approaches. Contextual multi-armed bandits have been studied for decades with various applications. To solve the exploitation-exploration tradeoff in bandits…

2022

Improved Algorithms for Neural Active Learning

NeurIPS 2022accept

We improve the theoretical and empirical performance of neural-network(NN)-based active learning algorithms for the non-parametric streaming setting. In particular, we introduce two regret metrics by minimizing the population loss that are more suitable in active learning than the one used in state-…