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Lixin Fan

22 accepted papers

2026

FedGRPO: Privately Optimizing Foundation Models with Group-Relative Rewards from Domain Clients

AAAI 2026technical

One important direction of Federated Foundation Models (FedFMs) is leveraging data from small client models to enhance the performance of a large server‑side foundation model. Existing methods based on model level or representation level knowledge transfer either require expensive local training or

Cited by 0SourcePDFScholar
2026

PrivSynth: Alternating and Control-Based Optimization for Privacy and Utility in Synthetic Data

CVPR 2026

As publicly available data dwindles, synthetic data generation (SDG) has become a practical solution for privacy-preserving data sharing. By training generative models on private data, SDG creates samples that retain task-relevant features while obfuscating sensitive content. However, recent work sh

Cited by 0SourceScholar
2026

Towards Privacy-Guaranteed Label Unlearning in Vertical Federated Learning: Few-Shot Forgetting Without Disclosure

ICLR 2026poster

This paper addresses the critical challenge of unlearning in Vertical Federated Learning (VFL), a setting that has received far less attention than its horizontal counterpart. Specifically, we propose the first method tailored to *label unlearning* in VFL, where labels play a dual role as both essen…

Cited by 0SourcecodeScholar
2025

FedCoT: Federated Chain-of-Thought Distillation for Large Language Models

EMNLP 2025

Large Language Models (LLMs) have emerged as a transformative force in artificial intelligence, demonstrating exceptional proficiency across various tasks. However, their deployment in resource-constrained environments and concerns over user data privacy pose significant challenges. In contrast, Sma

2025

FedMIA: An Effective Membership Inference Attack Exploiting "All for One" Principle in Federated Learning

CVPR 2025poster

Federated Learning (FL) is a promising approach for training machine learning models on decentralized data while preserving privacy. However, privacy risks, particularly Membership Inference Attacks (MIAs), which aim to determine whether a specific data point belongs to a target client's training se…

2025

FedMKT: Federated Mutual Knowledge Transfer for Large and Small Language Models

COLING 2025main

Recent research in federated large language models (LLMs) has primarily focused on enabling clients to fine-tune their locally deployed homogeneous LLMs collaboratively or on transferring knowledge from server-based LLMs to small language models (SLMs) at downstream clients. However, a significant g…

2025

Handling Spatial-Temporal Data Heterogeneity for Federated Continual Learning via Tail Anchor

CVPR 2025poster

Federated Continual Learning (FCL) allows each client to continually update its knowledge from task streams, enhancing the applicability of federated learning in real-world scenarios. However, FCL needs to address not only spatial data heterogeneity between clients but also temporal data heterogenei…

2025

Model-based Large Language Model Customization as Service

EMNLP 2025

Prominent Large Language Model (LLM) services from providers like OpenAI and Google excel at general tasks but often underperform on domain-specific applications. Current customization services for these LLMs typically require users to upload data for fine-tuning, posing significant privacy risks. W

2025

Order-Level Attention Similarity Across Language Models: A Latent Commonality

NeurIPS 2025poster

In this paper, we explore an important yet previously neglected question: Do context aggregation patterns across Language Models (LMs) share commonalities? While some works have investigated context aggregation or attention weights in LMs, they typically focus on individual models or attention heads…

Cited by 0SourcecodeScholar
2025

PPC-GPT: Federated Task-Specific Compression of Large Language Models via Pruning and Chain-of-Thought Distillation

EMNLP 2025

Compressing Large Language Models (LLMs) into task-specific Small Language Models (SLMs) encounters two significant challenges: safeguarding domain-specific knowledge privacy and managing limited resources. To tackle these challenges, we propose PPC-GPT, a novel unified framework that systematically

2024

Complementary Knowledge Distillation for Robust and Privacy-Preserving Model Serving in Vertical Federated Learning

AAAI 2024technical

Vertical Federated Learning (VFL) enables an active party with labeled data to enhance model performance (utility) by collaborating with multiple passive parties that possess auxiliary features corresponding to the same sample identifiers (IDs). Model serving in VFL is vital for real-world, delay-se…

Cited by 7SourcePDFScholar
2024

Diffusion-Driven Data Replay: A Novel Approach to Combat Forgetting in Federated Class Continual Learning

ECCV 2024oral

"Federated Class Continual Learning (FCCL) merges the challenges of distributed client learning with the need for seamless adaptation to new classes without forgetting old ones. The key challenge in FCCL is catastrophic forgetting, an issue that has been explored to some extent in Continual Learning…

2024

Ferrari: Federated Feature Unlearning via Optimizing Feature Sensitivity

NeurIPS 2024poster

The advent of Federated Learning (FL) highlights the practical necessity for the ’right to be forgotten’ for all clients, allowing them to request data deletion from the machine learning model’s service provider. This necessity has spurred a growing demand for Federated Unlearning (FU). Feature unle…

2024

Unlearning during Learning: An Efficient Federated Machine Unlearning Method

IJCAI 2024poster

In recent years, Federated Learning (FL) has garnered significant attention as a distributed machine learning paradigm. To facilitate the implementation of the "right to be forgotten," the concept of federated machine unlearning (FMU) has also emerged. However, current FMU approaches often involve a…

2023

FedPass: Privacy-Preserving Vertical Federated Deep Learning with Adaptive Obfuscation

IJCAI 2023poster

Vertical federated learning (VFL) allows an active party with labeled data to leverage auxiliary features from the passive parties to improve model performance. Concerns about the private feature and label leakage in both the training and inference phases of VFL have drawn wide research attention. I…

Cited by 18SourcePDFScholar
2022

FedCG: Leverage Conditional GAN for Protecting Privacy and Maintaining Competitive Performance in Federated Learning

IJCAI 2022poster

Federated learning (FL) aims to protect data privacy by enabling clients to build machine learning models collaboratively without sharing their private data. Recent works demonstrate that information exchanged during FL is subject to gradient-based privacy attacks and, consequently, a variety of pri…

Cited by 90SourcePDFScholar
2022

You Don’t Know My Favorite Color: Preventing Dialogue Representations from Revealing Speakers’ Private Personas

NAACL 2022long

Social chatbots, also known as chit-chat chatbots, evolve rapidly with large pretrained language models. Despite the huge progress, privacy concerns have arisen recently: training data of large language models can be extracted via model inversion attacks. On the other hand, the datasets used for tra…

2021

Protecting Intellectual Property of Generative Adversarial Networks From Ambiguity Attacks

CVPR 2021poster

Ever since Machine Learning as a Service emerges as a viable business that utilizes deep learning models to generate lucrative revenue, Intellectual Property Right (IPR) has become a major concern because these deep learning models can easily be replicated, shared, and re-distributed by any unauthor…

Cited by 94PDFScholar
2020

Deep Polarized Network for Supervised Learning of Accurate Binary Hashing Codes

IJCAI 2020poster

This paper proposes a novel deep polarized network (DPN) for learning to hash, in which each channel in the network outputs is pushed far away from zero by employing a differentiable bit-wise hinge-like loss which is dubbed as polarization loss. Reformulated within a generic Hamming Distance Metric…

Cited by 0SourcePDFScholar
2019

Rethinking Deep Neural Network Ownership Verification: Embedding Passports to Defeat Ambiguity Attacks

NeurIPS 2019poster

With substantial amount of time, resources and human (team) efforts invested to explore and develop successful deep neural networks (DNN), there emerges an urgent need to protect these inventions from being illegally copied, redistributed, or abused without respecting the intellectual properties of…

2017

Revisit Fuzzy Neural Network: Demystifying Batch Normalization and ReLU with Generalized Hamming Network

NeurIPS 2017poster

We revisit fuzzy neural network with a cornerstone notion of generalized hamming distance, which provides a novel and theoretically justified framework to re-interpret many useful neural network techniques in terms of fuzzy logic. In particular, we conjecture and empirically illustrate that, the cel…

Cited by 32SourcePDFScholar