557 research outputs found
High-Dimensional Stochastic Gradient Quantization for Communication-Efficient Edge Learning
Edge machine learning involves the deployment of learning algorithms at the
wireless network edge so as to leverage massive mobile data for enabling
intelligent applications. The mainstream edge learning approach, federated
learning, has been developed based on distributed gradient descent. Based on
the approach, stochastic gradients are computed at edge devices and then
transmitted to an edge server for updating a global AI model. Since each
stochastic gradient is typically high-dimensional (with millions to billions of
coefficients), communication overhead becomes a bottleneck for edge learning.
To address this issue, we propose in this work a novel framework of
hierarchical stochastic gradient quantization and study its effect on the
learning performance. First, the framework features a practical hierarchical
architecture for decomposing the stochastic gradient into its norm and
normalized block gradients, and efficiently quantizes them using a uniform
quantizer and a low-dimensional codebook on a Grassmann manifold, respectively.
Subsequently, the quantized normalized block gradients are scaled and cascaded
to yield the quantized normalized stochastic gradient using a so-called hinge
vector designed under the criterion of minimum distortion. The hinge vector is
also efficiently compressed using another low-dimensional Grassmannian
quantizer. The other feature of the framework is a bit-allocation scheme for
reducing the quantization error. The scheme determines the resolutions of the
low-dimensional quantizers in the proposed framework. The framework is proved
to guarantee model convergency by analyzing the convergence rate as a function
of the quantization bits. Furthermore, by simulation, our design is shown to
substantially reduce the communication overhead compared with the
state-of-the-art signSGD scheme, while both achieve similar learning
accuracies
Learning Data-Driven Vector-Quantized Degradation Model for Animation Video Super-Resolution
Existing real-world video super-resolution (VSR) methods focus on designing a
general degradation pipeline for open-domain videos while ignoring data
intrinsic characteristics which strongly limit their performance when applying
to some specific domains (eg., animation videos). In this paper, we thoroughly
explore the characteristics of animation videos and leverage the rich priors in
real-world animation data for a more practical animation VSR model. In
particular, we propose a multi-scale Vector-Quantized Degradation model for
animation video Super-Resolution (VQD-SR) to decompose the local details from
global structures and transfer the degradation priors in real-world animation
videos to a learned vector-quantized codebook for degradation modeling. A
rich-content Real Animation Low-quality (RAL) video dataset is collected for
extracting the priors. We further propose a data enhancement strategy for
high-resolution (HR) training videos based on our observation that existing HR
videos are mostly collected from the Web which contains conspicuous compression
artifacts. The proposed strategy is valid to lift the upper bound of animation
VSR performance, regardless of the specific VSR model. Experimental results
demonstrate the superiority of the proposed VQD-SR over state-of-the-art
methods, through extensive quantitative and qualitative evaluations of the
latest animation video super-resolution benchmark. The code and pre-trained
models can be downloaded at https://github.com/researchmm/VQD-SR
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