Fengbin Zhu

dblp:283/4845 · DBLP profile ↗
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9ranked-venue papers in the field
2as first author
9since 2021 · last 2026
0000-0001-6776-2040ORCID · verified

Domains — venue-derived; a paper can count in several

Information Retrieval & Web Search · 8 (2 first)Database Systems & Data Management · 1
YearPublicationVenuePosition
2026 MURE: Hierarchical Multi-Resolution Encoding via Vision-Language Models for Visual Document Retrieval
abstract
Visual Document Retrieval (VDR) requires representations that capture both fine-grained visual details and global document structure to ensure retrieval efficacy while maintaining computational efficiency. Existing VDR models struggle to balance effectiveness and efficiency when processing high-resolution documents: they often either lose fine-grained information or generate an excessive number of visual tokens, resulting in significant indexing overhead and high retrieval latency. In this work, we rethink the visual encoding mechanism and propose a new X-VisEmb paradigm that progresses from multi-resolution sampling and encoding, through cross-granularity feature fusion, to adaptive representation distillation. A preliminary study validates its feasibility and effectiveness in capturing complementary visual cues at varying scales. Building on the insights, we develop MURE , a novel framework that employs VLMs as a hierarchical multi-resolution encoder, integrates resolution-level Matryoshka representation learning (RMRL) for effective feature fusion, and applies a semantic-aware hierarchical clustering mechanism for visual token compression. Experiments on two widely used VDR benchmarks show that our MURE framework consistently beats strong baselines. Furthermore, it significantly outperforms ColPali with only 50% of its visual token budget.
Fengbin Zhu, Zijing Cai, Pengyang Shao, Wenjie Wang 0007, Fuli Feng, Richang Hong, Tat-Seng Chua
ICMR1
2026 One Adapts to Any: Meta Reward Modeling for Personalized LLM Alignment
abstract
Alignment of Large Language Models (LLMs) aims to align outputs with human preferences, and personalized alignment further adapts models to individual users. This relies on personalized reward models that capture user-specific preferences and automatically provide individualized feedback. However, developing these models faces two critical challenges: the scarcity of feedback from individual users and the need for efficient adaptation to unseen users. We argue that addressing these constraints requires a paradigm shift from fitting static user models to ''learning to learn'' adaptation. To realize this, we propose Meta Reward Modeling (MRM), which reformulates personalized reward modeling as a meta-learning problem. Specifically, we represent each user's reward model as a weighted combination of base reward functions, and optimize the initialization of these weights using a Model-Agnostic Meta-Learning (MAML)-style framework to support fast adaptation under limited feedback. To ensure robustness, we introduce the Robust Personalization Objective (RPO), which places greater emphasis on hard-to-learn users during meta optimization. Extensive experiments on personalized preference datasets validate that MRM enhances few-shot personalization, improves user robustness, and consistently outperforms baselines. We release code at https://github.com/ModalityDance/MRM.
Hongru Cai, Yongqi Li 0001, Tiezheng Yu, Fengbin Zhu, Wenjie Wang 0007, Fuli Feng, Wenjie Li 0002
SIGIR4
2026 BalDRO: A Distributionally Robust Optimization based Framework for Large Language Model Unlearning
abstract
As Large Language Models (LLMs) increasingly shape online content, how to remove targeted information from well-trained LLMs (also known as LLM unlearning) has become increasingly critical for web governance. A key challenge in LLM unlearning lies in the sample-wise imbalance within the forget set: different samples exhibit widely varying unlearning difficulty, leading to asynchronous forgetting speeds where some knowledge remains insufficiently erased while others become over-forgotten. To address this challenge, we propose BalDRO, a novel and efficient framework for balanced LLM unlearning. BalDRO formulates unlearning as a min–sup process, where the inner process identifies a worst-case data distribution that adaptively emphasizes hard-to-unlearn samples, while the outer process updates model parameters based on the worst-case data distribution. We instantiate this formulation through two efficient variants: BalDRO-G, a discrete GroupDRO-based approximation that focuses on high-loss subsets, and BalDRO-DV, a continuous Donsker–Varadhan dual method that enables smooth, adaptive weighting within standard LLM training pipelines. Extensive experiments on the TOFU and MUSE benchmarks demonstrate the effectiveness of our proposed BalDRO, yielding significant improvements in both forgetting quality and model utility over existing methods. For reproducibility, we have released the code for BalDRO. https://github.com/nxZhai/BalDRO.
Pengyang Shao, Naixin Zhai, Lei Chen 0051, Yonghui Yang 0001, Fengbin Zhu, Xun Yang 0001, Meng Wang 0001
WWW5
2026 Reason4Rec: Deliberative User Preference Alignment of Large Language Models for Recommendation
abstract
Aligning Large Language Models (LLMs) with recommendation tasks represents an emerging paradigm in recommendation domain, exhibiting promising performance overall. However, these aligned recommendation LLMs often struggle with complex scenarios due to limitations in the current alignment task formulation, which optimizes LLMstodirectly generate user feedback without deliberation. To develop more reliable recommendation LLMs, we introduce a new Deliberative Recommendation task, which enforces explicit reasoning about user preferences as an additional alignment objective. To address this task, we propose a Reasoning-powered Recommender framework designed to enhance reasoning capabilities by leveraging verbalized user feedback in a step-wise manner. Specifically, this framework employs collaborative step-wise experts alongside specifically crafted expert-wise training strategies. Extensive experiments conducted on three real-world datasets demonstrate the rationality of the deliberative task formulation and the effectiveness of the proposed framework in improving both pre diction accuracy and reasoning quality. Our implementation is publicly available on GitHub: https://github.com/Peter-Fy/Reason4Rec.
Yi Fang 0010, Wenjie Wang 0007, Yang Zhang 0072, Fengbin Zhu, Qifan Wang 0001, Fuli Feng, Xiangnan He 0001
IEEE Trans. Knowl. Data Eng.4
2025 Heterogeneous User Modeling for LLM-based Recommendation
Honghui Bao, Wenjie Wang 0007, Xinyu Lin 0001, Fengbin Zhu, Fuli Feng, Tat-Seng Chua
RecSys4
2025 Unified Category and Style Generalization for Instance-Level Sketch Retrieval
abstract
Zero-shot instance-level sketch retrieval addresses a practical retrieval scenario in which sketches from unseen categories during training serve as queries to retrieve matching RGB images. The core challenges of this task lie in two aspects: unknown category generalization and subjective style adaptation. Existing methods either focus solely on category generalization or apply simplistic style elimination techniques within a specific category, leading to suboptimal performance when both challenges are present. To this end, we propose the Dual-Attentive Prompt (DAP) method, which unifies category generalization and style adaptation into a single, interpretable framework. Central to DAP is a dual-attentive prompt composer, consisting of two self-attention-based modules. This composer dynamically integrates pre-learned category-specific knowledge with instance-specific prompts that adapt to sketch-specific styles. By cooperating with additional style alignment loss, the proposed method ensures robust generalization of unseen categories while mitigating the impact of subjective style variations. Extensive experimental results demonstrate the state-of-the-art performance of the proposed method. Additionally, some insights are provided into the challenges of traditional training processes when handling multi-style sketches, along with quantitative and qualitative evidence showing how the proposed approach effectively mitigates the negative impact of subjective style variations.
Zechao Hu 0003, Zhengwei Yang 0001, Hao Li 0093, Yixiong Zou, Fengbin Zhu, Zheng Wang 0007
SIGIR5
2025 Long Context vs. RAG: Strategies for Processing Long Documents in LLMs
abstract
Large Language Models (LLMs) excel at zero- and few-shot learning but are restricted by the length of context windows when processing long documents. Two strategies have emerged to overcome this limitation: (1) Long Context (LC) methods, which extend or compress transformer architectures to input more text; and (2) Retrieval-Augmented Generation (RAG), which integrates external knowledge sources via embedding- or index-based retrieval. This half-day tutorial offers a unified, beginner-friendly introduction to both approaches. We first review transformer fundamentals-positional encoding, attention complexity, and common LC techniques. Next, we explain the classic RAG pipeline and recent RAG strategies, alongside evaluation metrics and benchmarks. We also analyze recent empirical studies to highlight strengths, limitations, and trade-offs of LC vs. RAG in terms of scalability, computational cost, and retrieval effectiveness. We conclude with best practices for real-world deployments, emerging hybrid architectures, and open research directions, equipping IR researchers and practitioners with actionable guidelines for processing long documents in LLMs.
Xinze Li 0001, Yushi Bai, Bowen Jin, Fengbin Zhu, Liangming Pan, Yixin Cao 0002
SIGIR4
2025 FinIR: The 2nd Workshop on Financial Information Retrieval in the Era of Generative AI
abstract
Recent advancements in Generative AI, such as Large Language Models (LLMs), have demonstrated remarkable success across various general tasks. Extensive studies have explored leveraging generative models in finance, but significant challenges persist. This half-day workshop explores potential approaches and research directions to address these challenges by equipping generative models with advanced Information Retrieval (IR) models. Specifically, this workshop seeks to provide a platform for discussing innovative ideas that facilitate the advancement of IR technology to enrich generative models in finance from four key perspectives: (i) financial IR techniques (ii) financial IR benchmarking and evaluation (iii) financial systems and agents/assistants (iv) and trustworthiness, privacy and security when applying financial IR and generative models. This workshop aims to deepen understanding, accelerate progress, and support the advancement of IR technology to enhance generative models to address financial challenges.
Fengbin Zhu, Yunshan Ma 0002, Fuli Feng, Chao Wang 0049, Huan-Bo Luan, Guangnan Ye, Shuo Zhang 0006, Dhagash Mehta, Pingping Chen 0004, Bing Xiang, Tat-Seng Chua
SIGIR1
2025 Large Language Models Empowered Personalized Web Agents
abstract
Web agents have emerged as a promising direction to automate Web task completion based on user instructions, significantly enhancing user experience. Recently, Web agents have evolved from traditional agents to Large Language Models (LLMs)-based Web agents. Despite their success, existing LLM-based Web agents overlook the importance of personalized data (e.g., user profiles and historical Web behaviors) in assisting the understanding of users' personalized instructions and executing customized actions.
Hongru Cai, Yongqi Li 0001, Wenjie Wang 0007, Fengbin Zhu, Xiaoyu Shen 0001, Wenjie Li 0002, Tat-Seng Chua
WWW4