Xiaojin Zhang 0002

dblp:69/8512-2 · DBLP profile ↗
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10ranked-venue papers in the field
4as first author
10since 2021 · last 2026
0000-0001-9065-6852ORCID · conflict

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

Data Mining & Knowledge Discovery · 6 (4 first)Database Systems & Data Management · 3Information Retrieval & Web Search · 1
YearPublicationVenuePosition
2026 InsQABench: Benchmarking Chinese insurance domain question answering with large language models
abstract
We present InsQABench-the first comprehensive benchmark for evaluating LLMs’ capabilities in Chinese insurance QA. InsQABench comprises 95K carefully curated QA pairs derived from real-world insurance documents, covering 3 distinct tasks, 44 question types, and 55 specialized insurance topics. Our experiments evaluated and reported the performance of mainstream LLMs under both fine-tuned and zero-shot settings, demonstrating that fine-tuning on InsQABench can significantly improve model performance. We also introduced two frameworks that further enhanced task-specific performance, achieving 4.91% and 5.11% enhancement in accuracy over the next best-performing model.
Binbin Lin 0002, Jiarui Cai, Xiaojin Zhang 0002, Zhongyu Wei, Wei Chen 0088
Inf. Process. Manag.8
2025 Grounding Foundation Models through Federated Transfer Learning: A General Framework
abstract
Foundation Models (FMs) such as GPT-4 encoded with vast knowledge and powerful emergent abilities have achieved remarkable success in various natural language processing and computer vision tasks. Grounding FMs by adapting them to domain-specific tasks or augmenting them with domain-specific knowledge enables us to exploit the full potential of FMs. However, grounding FMs faces several challenges, stemming primarily from constrained computing resources, data privacy, model heterogeneity, and model ownership. Federated Transfer Learning (FTL), the combination of federated learning and transfer learning, provides promising solutions to address these challenges. Recently, the need for grounding FMs leveraging FTL, coined FTL-FM, has arisen strongly in both academia and industry. Motivated by the strong growth in FTL-FM research and the potential impact of FTL-FM on industrial applications, we propose an FTL-FM framework that formulates problems of grounding FMs in the federated learning setting, construct a detailed taxonomy based on the FTL-FM framework to categorize state-of-the-art FTL-FM works, and comprehensively overview FTL-FM works based on the proposed taxonomy. We also establish correspondence between FTL-FM and conventional phases of adapting FM so that FM practitioners can align their research works with FTL-FM. In addition, we overview advanced efficiency-improving and privacy-preserving techniques because efficiency and privacy are critical concerns in FTL-FM. Last, we discuss opportunities and future research directions of FTL-FM.
Yan Kang 0001, Tao Fan 0002, Hanlin Gu, Xiaojin Zhang 0002, Lixin Fan, Qiang Yang 0001
ACM Trans. Intell. Syst. Technol.4
2025 Ten Challenging Problems in Federated Foundation Models
abstract
Federated Foundation Models (FedFMs) represent a distributed learning paradigm that fuses general competences of foundation models as well as privacy-preserving capabilities of federated learning. This combination allows the large foundation models and the small local domain models at the remote clients to learn from each other in a teacher-student learning setting. This paper provides a comprehensive summary of the ten challenging problems inherent in FedFMs, encompassing foundational theory, utilization of private data, continual learning, unlearning, Non-IID and graph data, bidirectional knowledge transfer, incentive mechanism design, game mechanism design, model watermarking, and efficiency. The ten challenging problems manifest in five pivotal aspects: “Foundational Theory,” which aims to establish a coherent and unifying theoretical framework for FedFMs. “Data,” addressing the difficulties in leveraging domain-specific knowledge from private data while maintaining privacy; “Heterogeneity,” examining variations in data, model, and computational resources across clients; “Security and Privacy,” focusing on defenses against malicious attacks and model theft; and “Efficiency,” highlighting the need for improvements in training, communication, and parameter efficiency. For each problem, we offer a clear mathematical definition on the objective function, analyze existing methods, and discuss the key challenges and potential solutions. This in-depth exploration aims to advance the theoretical foundations of FedFMs, guide practical implementations, and inspire future research to overcome these obstacles, thereby enabling the robust, efficient, and privacy-preserving FedFMs in various real-world applications.
Tao Fan 0002, Hanlin Gu, Xuemei Cao 0001, Chee Seng Chan, Qian Chen 0023, Yiqiang Chen 0001, Yihui Feng, Yang Gu 0001, Jiaxiang Geng, Bing Luo 0002, Shuoling Liu, WinKent Ong, Chao Ren 0006, Jiaqi Shao, Xiaoli Tang 0001, Hong Xi Tae, Yongxin Tong, Shuyue Wei 0001, Fan Wu 0006, Wei Xi 0003, Mingcong Xu, Xin Yang 0012, Jiangpeng Yan, Hao Yu 0023, Han Yu 0001, Xiaojin Zhang 0002, Zhenzhe Zheng 0001, Lixin Fan, Qiang Yang 0001
IEEE Trans. Knowl. Data Eng.30
2025 Camouflaged Variational Graph AutoEncoder Against Attribute Inference Attacks for Cross-Domain Recommendation
abstract
Cross-domain recommendation (CDR) aims to alleviate the data sparsity problem by leveraging the benefits of modeling two domains. However, existing research often focuses on the recommendation performance while ignores the privacy leakage issue. We find that an attacker can infer user attribute information from the knowledge (e.g., user preferences) transferred between the source and target domains. For example, in our experiments, the average inference accuracies of attack models on gender and age attributes are 0.8323 and 0.3897. The best-performing attack model achieves accuracies of 0.8847 and 0.4634, exceeding a random inference by 25.10% and 64.04%. We can see that the leakage of user attribute information may significantly exceed what would be expected from random inference. In this paper, we propose a novel recommendation framework named CVGAE (short for camouflaged variational graph autoencoder), which effectively models user behaviors and mitigates the risk of user attribute information leakage at the same time. Specifically, our CVGAE combines the strengths of VAEs in capturing latent features and variability with the ability of GCNs in exploiting high-order relational information. Moreover, to ensure against attribute inference attacks without sacrificing the recommendation performance, we design a user attribute protection module that fuses user attribute-camouflaged information with knowledge transfer during cross-domain processes. We then conduct extensive experiments on three real-world datasets, and find our CVGAE is able to achieve strong privacy protection while making little sacrifices in recommendation accuracy.
Yudi Xiong, Yongxin Guo 0001, Weike Pan, Qiang Yang 0001, Zhong Ming 0001, Xiaojin Zhang 0002, Han Yu 0001, Tao Lin 0004, Xiaoying Tang 0002
IEEE Trans. Knowl. Data Eng.6
2024 Model Trip: Enhancing Privacy and Fairness in Model Fusion Across Multi-Federations for Trustworthy Global Healthcare
abstract
Federated Learning has emerged as a revolutionary innovation in the evolving landscape of global healthcare, fostering collaboration among institutions and facilitating collaborative data analysis. As practical applications continue to proliferate, numerous federations have formed in different regions. The optimization and sustainable development of federation-pretrained models have emerged as new challenges. These challenges primarily encompass privacy, population shift and data dependency, which may lead to severe consequences such as the leakage of sensitive information within models and training samples, unfair model performance and resource burdens. To tackle these issues, we propose FairFusion, a cross-federation model fusion approach that enhances privacy and fairness. FairFusion operates across federations within a Model Trip paradigm, integrating knowledge from diverse federations to continually enhance model performance. Through federated model fusion, multi-objective quantification and optimization, FairFusion obtains trustworthy solutions that excel in utility, privacy and fairness. We conduct comprehensive experiments on three public real-world healthcare datasets. The results demonstrate that FairFusion achieves outstanding model fusion performance in terms of utility and fairness across various model structures and subgroups with sensitive attributes while guaranteeing model privacy.
Qian Chen 0023, Yiqiang Chen 0001, Bingjie Yan, Xinlong Jiang, Xiaojin Zhang 0002, Yan Kang 0001, Wuliang Huang, Chenlong Gao, Lixin Fan, Qiang Yang 0001
ICDE5
2024 Secure Dataset Condensation for Privacy-Preserving and Efficient Vertical Federated Learning
Dashan Gao 0002, Canhui Wu, Xiaojin Zhang 0002, Xin Yao 0001, Qiang Yang 0001
ECML/PKDD (1)3
2024 A Game-theoretic Framework for Privacy-preserving Federated Learning
abstract
In federated learning, benign participants aim to optimize a global model collaboratively. However, the risk of privacy leakage cannot be ignored in the presence of semi-honest adversaries. Existing research has focused either on designing protection mechanisms or on inventing attacking mechanisms. While the battle between defenders and attackers seems never-ending, we are concerned with one critical question: Is it possible to prevent potential attacks in advance? To address this, we propose the first game-theoretic framework that considers both FL defenders and attackers in terms of their respective payoffs, which include computational costs, FL model utilities, and privacy leakage risks. We name this game the federated learning privacy game (FLPG), in which neither defenders nor attackers are aware of all participants’ payoffs. To handle the incomplete information inherent in this situation, we propose associating the FLPG with an oracle that has two primary responsibilities. First, the oracle provides lower and upper bounds of the payoffs for the players. Second, the oracle acts as a correlation device, privately providing suggested actions to each player. With this novel framework, we analyze the optimal strategies of defenders and attackers. Furthermore, we derive and demonstrate conditions under which the attacker, as a rational decision-maker, should always follow the oracle’s suggestion not to attack .
Xiaojin Zhang 0002, Lixin Fan, Wenjie Li 0008, Kai Chen 0005, Qiang Yang 0001
ACM Trans. Intell. Syst. Technol.1
2024 A Meta-Learning Framework for Tuning Parameters of Protection Mechanisms in Trustworthy Federated Learning
abstract
Trustworthy federated learning typically leverages protection mechanisms to guarantee privacy. However, protection mechanisms inevitably introduce utility loss or efficiency reduction while protecting data privacy. Therefore, protection mechanisms and their parameters should be carefully chosen to strike an optimal tradeoff amongprivacy leakage,utility loss, andefficiency reduction. To this end, federated learning practitioners need tools to measure the three factors and optimize the tradeoff between them to choose the protection mechanism that is most appropriate to the application at hand. Motivated by this requirement, we propose a framework that (1) formulates trustworthy federated learning as a problem of finding a protection mechanism to optimize the tradeoff among privacy leakage, utility loss, and efficiency reduction and (2) formally defines bounded measurements of the three factors. We then propose a meta-learning algorithm to approximate this optimization problem and find optimal protection parameters for representative protection mechanisms, including randomization, homomorphic encryption, secret sharing, and compression. We further design estimation algorithms to quantify these found optimal protection parameters in a practical horizontal federated learning setting and provide a theoretical analysis of the estimation error.
Xiaojin Zhang 0002, Yan Kang 0001, Lixin Fan, Kai Chen 0005, Qiang Yang 0001
ACM Trans. Intell. Syst. Technol.1
2023 No Free Lunch Theorem for Security and Utility in Federated Learning
abstract
In a federated learning scenario where multiple parties jointly learn a model from their respective data, there exist two conflicting goals for the choice of appropriate algorithms. On one hand, private and sensitive training data must be kept secure as much as possible in the presence of semi-honest partners; on the other hand, a certain amount of information has to be exchanged among different parties for the sake of learning utility. Such a challenge calls for the privacy-preserving federated learning solution, which maximizes the utility of the learned model and maintains a provable privacy guarantee of participating parties’ private data. This article illustrates a general framework that (1) formulates the trade-off between privacy loss and utility loss from a unified information-theoretic point of view, and (2) delineates quantitative bounds of the privacy-utility trade-off when different protection mechanisms including randomization, sparsity, and homomorphic encryption are used. It was shown that in general there is no free lunch for the privacy-utility trade-off , and one has to trade the preserving of privacy with a certain degree of degraded utility. The quantitative analysis illustrated in this article may serve as the guidance for the design of practical federated learning algorithms.
Xiaojin Zhang 0002, Hanlin Gu, Lixin Fan, Kai Chen 0005, Qiang Yang 0001
ACM Trans. Intell. Syst. Technol.1
2023 Trading Off Privacy, Utility, and Efficiency in Federated Learning
abstract
Federated learning (FL) enables participating parties to collaboratively build a global model with boosted utility without disclosing private data information. Appropriate protection mechanisms have to be adopted to fulfill the opposing requirements in preserving privacy and maintaining high model utility . In addition, it is a mandate for a federated learning system to achieve high efficiency in order to enable large-scale model training and deployment. We propose a unified federated learning framework that reconciles horizontal and vertical federated learning. Based on this framework, we formulate and quantify the trade-offs between privacy leakage, utility loss, and efficiency reduction, which leads us to the No-Free-Lunch (NFL) theorem for the federated learning system. NFL indicates that it is unrealistic to expect an FL algorithm to simultaneously provide excellent privacy, utility, and efficiency in certain scenarios. We then analyze the lower bounds for the privacy leakage, utility loss, and efficiency reduction for several widely-adopted protection mechanisms, including Randomization , Homomorphic Encryption , Secret Sharing, and Compression . Our analysis could serve as a guide for selecting protection parameters to meet particular requirements.
Xiaojin Zhang 0002, Yan Kang 0001, Kai Chen 0005, Lixin Fan, Qiang Yang 0001
ACM Trans. Intell. Syst. Technol.1