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Dazhao Cheng

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5 papers

2 author rows

TAAS Journal 2026 Journal Article

FlePo: GPU Multi-task Scheduling Optimization Framework for Dynamic Scenes

Huanghuang Liang
Xin Yang
Rui Ge
Yaqi Xia
Chuang Hu
Xiaobo Zhou
Dazhao Cheng

Deep Neural Networks (DNNs) are widely used in intelligent applications, driving increasing computational demands on GPUs. However, modern GPU multitasking scheduling algorithms fail to effectively balance real-time task performance and resource utilization, especially under dynamic workloads with highly variable DNN computational demands. The complex and workload-dependent execution times of DNN kernels often lead to inefficient resource allocation, degraded system throughput, and missed real-time constraints. To address these challenges, we propose FlePo (Flexible Parallel Orchestrator), a GPU multitasking scheduling framework designed to optimize resource utilization and maintain real-time task performance within acceptable limits for soft real-time systems. FlePo integrates two key techniques: Adaptive Padding Dispatch (APD), which dynamically schedules best-effort tasks while leveraging the predictable execution characteristics of DNN kernels to maintain real-time predictability; and Dynamic Parallel Fusion (DPF), which employs kernel fusion to create computational isolation, reducing interference in parallel job execution. By combining offline profiling with online adaptation, FlePo efficiently responds to workload variations. We evaluate FlePo on two heterogeneous GPU platforms, NVIDIA Tesla V100 and AMD MI50, achieving up to a 50% increase in throughput while keeping real-time overhead below 2%. Our work enhances GPU multitasking in dynamic environments, with potential applications in autonomous driving, smart homes, and intelligent healthcare.

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AAAI Conference 2026 Conference Paper

REMISVFU: Vertical Federated Unlearning via Representation Misdirection for Intermediate Output Feature

Wenhan Wu
Zhili He
Huanghuang Liang
Yili Gong
Jiawei Jiang
Chuang Hu
Dazhao Cheng

Data-protection regulations such as the GDPR grant every participant in a federated system a right to be forgotten. Federated unlearning has therefore emerged as a research frontier, aiming to remove a specific party's contribution from the learned model while preserving the utility of the remaining parties. However, most unlearning techniques focus on Horizontal Federated Learning (HFL), where data are partitioned by samples. In contrast, Vertical Federated Learning (VFL) allows organizations that possess complementary feature spaces to train a joint model without sharing raw data. The resulting feature-partitioned architecture renders HFL-oriented unlearning methods ineffective. In this paper, we propose ReMisVFU, a plug-and-play representation-misdirection framework that enables fast, client-level unlearning in splitVFL systems. When a deletion request arrives, the forgetting party collapses its encoder output to a randomly sampled anchor on the unit sphere, severing the statistical link between its features and the global model. To maintain utility for the remaining parties, the server jointly optimizes a retention loss and a forgetting loss, aligning their gradients via orthogonal projection to eliminate destructive interference. Evaluations on public benchmarks show that ReMisVFU suppresses back-door attack success to the natural class-prior level and sacrifices only about 2.5% points of clean accuracy, outperforming state-of-the-art baselines.

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IJCAI Conference 2025 Conference Paper

Zero-shot Federated Unlearning via Transforming from Data-Dependent to Personalized Model-Centric

Wenhan Wu
Huanghuang Liang
Jingling Yuan
Jiawei Jiang
Kanye Ye Wang
Chuang Hu
Xiaobo Zhou
Dazhao Cheng

Federated Unlearning (FU) addresses the "right to be forgotten" in federated learning by removing specific client data's contribution without retraining from scratch. Existing FUs are data-dependent, which make the assumption that systems can access original training data or stored historical parameter updates during unlearning. However, the assumption cannot always hold in practice, as users usually request the deletion of client data and historical parameter updates due to privacy concerns or storage limitations. Therefore, it is crucial to develop a zero-shot FU method without such data access. The key challenge is how to distinguish and remove the impact of target clients without data-level information. Motivated by the idea that if we can learn client-specific personalized information from the model instead of data, FU can be model-centric and data-free, we present the first zero-shot FU framework ZeroFU. By embedding client contributions into the model during learning via condition computation, ZeroFU enables the model to possess personalized features for unlearning. The unlearning is achieved using a proposed GAN-based distillation framework that obfuscates the personalized feature of the target client. Evaluations demonstrate its effectiveness in unlearning under non-IID settings.

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ECAI Conference 2024 Conference Paper

Diversifying the Mixture-of-Experts Representation for Language Models with Orthogonal Optimizer

Boan Liu
Liang Ding 0006
Li Shen 0008
Keqin Peng
Yu Cao 0014
Dazhao Cheng
Dacheng Tao

The Mixture of Experts (MoE) has emerged as a highly successful technique in deep learning, based on the principle of divide-and-conquer to maximize model capacity without significant additional computational cost. Even in the era of large-scale language models (LLMs), MoE continues to play a crucial role, as some researchers have indicated that GPT-4 adopts the MoE structure to ensure diverse inference results. However, MoE is susceptible to performance degeneracy, particularly evident in the issues of imbalance and homogeneous representation among experts. While previous studies have extensively addressed the problem of imbalance, the challenge of homogeneous representation remains unresolved. In this study, we shed light on the homogeneous representation problem, wherein experts in the MoE fail to specialize and lack diversity, leading to frustratingly high similarities in their representations (up to 99% in a well-performed MoE model). This problem restricts the expressive power of the MoE and, we argue, contradicts its original intention. To tackle this issue, we propose a straightforward yet highly effective solution: OMoE, an orthogonal expert optimizer. Additionally, we introduce an alternating training strategy that encourages each expert to update in a direction orthogonal to the subspace spanned by other experts. Our algorithm facilitates MoE training in two key ways: firstly, it explicitly enhances representation diversity, and secondly, it implicitly fosters interaction between experts during orthogonal weights computation. Through extensive experiments, we demonstrate that our proposed optimization algorithm significantly improves the performance of fine-tuning the MoE model on the GLUE benchmark, SuperGLUE benchmark, question-answering task, and name entity recognition tasks.

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TAAS Journal 2015 Journal Article

Self-Tuning Batching with DVFS for Performance Improvement and Energy Efficiency in Internet Servers

Dazhao Cheng
Yanfei Guo
Changjun Jiang
Xiaobo Zhou

Performance improvement and energy efficiency are two important goals in provisioning Internet services in datacenter servers. In this article, we propose and develop a self-tuning request batching mechanism to simultaneously achieve the two correlated goals. The batching mechanism increases the cache hit rate at the front-tier Web server, which provides the opportunity to improve an application’s performance and the energy efficiency of the server system. The core of the batching mechanism is a novel and practical two-layer control system that adaptively adjusts the batching interval and frequency states of CPUs according to the service level agreement and the workload characteristics. The batching control adopts a self-tuning fuzzy model predictive control approach for application performance improvement. The power control dynamically adjusts the frequency of Central Processing Units (CPUs) with Dynamic Voltage and Frequency Scaling (DVFS) in response to workload fluctuations for energy efficiency. A coordinator between the two control loops achieves the desired performance and energy efficiency. We further extend the self-tuning batching with DVFS approach from a single-server system to a multiserver system. It relies on a MIMO expert fuzzy control to adjust the CPU frequencies of multiple servers and coordinate the frequency states of CPUs at different tiers. We implement the mechanism in a test bed. Experimental results demonstrate that the new approach significantly improves the application performance in terms of the system throughput and average response time. At the same time, the results also illustrate the mechanism can reduce the energy consumption of a single-server system by 13% and a multiserver system by 11%, respectively.

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