二进制神经网络（BNNS）将原始的全精度权重和激活为1位，带有符号功能。由于传统符号函数的梯度几乎归零，因此不能用于反向传播，因此已经提出了几次尝试来通过使用近似梯度来缓解优化难度。然而，这些近似损坏了事实梯度的主要方向。为此，我们建议使用用于训练BNN的正弦函数的组合来估计傅立叶频域中的符号功能的梯度，即频域近似（FDA）。该提出的方法不会影响占据大部分整体能量的原始符号功能的低频信息，并且将忽略高频系数以避免巨大的计算开销。此外，我们将噪声适配模块嵌入到训练阶段以补偿近似误差。关于多个基准数据集和神经架构的实验说明了使用我们的方法学习的二进制网络实现了最先进的准确性。代码将在\ texit {https://gitee.com/mindspore/models/tree/master/research/cv/fda-bnn}上获得。

This paper studies the problem of designing compact binary architectures for vision multi-layer perceptrons (MLPs). We provide extensive analysis on the difficulty of binarizing vision MLPs and find that previous binarization methods perform poorly due to limited capacity of binary MLPs. In contrast with the traditional CNNs that utilizing convolutional operations with large kernel size, fully-connected (FC) layers in MLPs can be treated as convolutional layers with kernel size $1\times1$. Thus, the representation ability of the FC layers will be limited when being binarized, and places restrictions on the capability of spatial mixing and channel mixing on the intermediate features. To this end, we propose to improve the performance of binary MLP (BiMLP) model by enriching the representation ability of binary FC layers. We design a novel binary block that contains multiple branches to merge a series of outputs from the same stage, and also a universal shortcut connection that encourages the information flow from the previous stage. The downsampling layers are also carefully designed to reduce the computational complexity while maintaining the classification performance. Experimental results on benchmark dataset ImageNet-1k demonstrate the effectiveness of the proposed BiMLP models, which achieve state-of-the-art accuracy compared to prior binary CNNs. The MindSpore code is available at \url{https://gitee.com/mindspore/models/tree/master/research/cv/BiMLP}.

模型二进制化是一种压缩神经网络并加速其推理过程的有效方法。但是，1位模型和32位模型之间仍然存在显着的性能差距。实证研究表明，二进制会导致前进和向后传播中的信息损失。我们提出了一个新颖的分布敏感信息保留网络（DIR-NET），该网络通过改善内部传播和引入外部表示，将信息保留在前后传播中。 DIR-NET主要取决于三个技术贡献：（1）最大化二进制（IMB）的信息：最小化信息损失和通过重量平衡和标准化同时同时使用权重/激活的二进制误差； （2）分布敏感的两阶段估计器（DTE）：通过共同考虑更新能力和准确的梯度来通过分配敏感的软近似来保留梯度的信息； （3）代表性二进制 - 意识蒸馏（RBD）：通过提炼完整精确和二元化网络之间的表示来保留表示信息。 DIR-NET从统一信息的角度研究了BNN的前进过程和后退过程，从而提供了对网络二进制机制的新见解。我们的DIR-NET中的三种技术具有多功能性和有效性，可以在各种结构中应用以改善BNN。关于图像分类和客观检测任务的综合实验表明，我们的DIR-NET始终优于主流和紧凑型体系结构（例如Resnet，vgg，vgg，EfficityNet，darts和mobilenet）下最新的二进制方法。此外，我们在现实世界中的资源有限设备上执行DIR-NET，该设备可实现11.1倍的存储空间和5.4倍的速度。

本文研究了重量和激活都将二进制神经网络（BNN）二进制为1位值，从而大大降低了记忆使用率和计算复杂性。由于现代深层神经网络具有复杂的设计，具有复杂的架构，其准确性，因此权重和激活分布的多样性非常高。因此，传统的符号函数不能很好地用于有效地在BNN中进行全精度值。为此，我们提出了一种称为Adabin的简单而有效的方法，可自适应获得最佳的二进制集$ \ {b_1，b_2 \} $（$ b_1，b_1，b_2 \ in \ mathbb {r} $）的重量和激活而不是固定集（即$ \ { - 1，+1 \} $）。通过这种方式，提出的方法可以更好地拟合不同的分布，并提高二进制特征的表示能力。实际上，我们使用中心位置和1位值的距离来定义新的二进制量化函数。对于权重，我们提出了一种均衡方法，将对称分布的对称中心与实价分布相对，并最大程度地减少它们的kullback-leibler差异。同时，我们引入了一种基于梯度的优化方法，以获取这两个激活参数，这些参数以端到端的方式共同训练。基准模型和数据集的实验结果表明，拟议的Adabin能够实现最新性能。例如，我们使用RESNET-18体系结构在Imagenet上获得66.4 \％TOP-1的精度，并使用SSD300获得了Pascal VOC的69.4映射。

依靠这样的前提是，二进制神经网络的性能可以在很大程度上恢复，而完全精确的权重向量与其相应的二进制向量之间的量化错误，网络二线化的现有作品经常采用模型鲁棒性的想法以达到上述目标。但是，鲁棒性仍然是一个不明智的概念，而没有扎实的理论支持。在这项工作中，我们介绍了Lipschitz的连续性，即定义明确的功能特性，是定义BNN模型鲁棒性的严格标准。然后，我们建议将Lipschitz连续性保留为正规化项，以提高模型的鲁棒性。特别是，虽然流行的Lipschitz涉及正则化方法由于其极端稀疏而经常在BNN中崩溃，但我们将保留矩阵设计以近似于目标重量矩阵的光谱规范，可以将其作为BNN的Lipschitz常数的近似值部署精确的L​​ipschitz恒定计算（NP-HARD）。我们的实验证明，我们的BNN特异性正则化方法可以有效地增强BNN的鲁棒性（在Imagenet-C上作证），从而在CIFAR和Imagenet上实现最新性能。

Although considerable progress has been obtained in neural network quantization for efficient inference, existing methods are not scalable to heterogeneous devices as one dedicated model needs to be trained, transmitted, and stored for one specific hardware setting, incurring considerable costs in model training and maintenance. In this paper, we study a new vertical-layered representation of neural network weights for encapsulating all quantized models into a single one. With this representation, we can theoretically achieve any precision network for on-demand service while only needing to train and maintain one model. To this end, we propose a simple once quantization-aware training (QAT) scheme for obtaining high-performance vertical-layered models. Our design incorporates a cascade downsampling mechanism which allows us to obtain multiple quantized networks from one full precision source model by progressively mapping the higher precision weights to their adjacent lower precision counterparts. Then, with networks of different bit-widths from one source model, multi-objective optimization is employed to train the shared source model weights such that they can be updated simultaneously, considering the performance of all networks. By doing this, the shared weights will be optimized to balance the performance of different quantized models, thus making the weights transferable among different bit widths. Experiments show that the proposed vertical-layered representation and developed once QAT scheme are effective in embodying multiple quantized networks into a single one and allow one-time training, and it delivers comparable performance as that of quantized models tailored to any specific bit-width. Code will be available.

We propose two efficient approximations to standard convolutional neural networks: Binary-Weight-Networks and XNOR-Networks. In Binary-Weight-Networks, the filters are approximated with binary values resulting in 32× memory saving. In XNOR-Networks, both the filters and the input to convolutional layers are binary. XNOR-Networks approximate convolutions using primarily binary operations. This results in 58× faster convolutional operations (in terms of number of the high precision operations) and 32× memory savings. XNOR-Nets offer the possibility of running state-of-the-art networks on CPUs (rather than GPUs) in real-time. Our binary networks are simple, accurate, efficient, and work on challenging visual tasks. We evaluate our approach on the ImageNet classification task. The classification accuracy with a Binary-Weight-Network version of AlexNet is the same as the full-precision AlexNet. We compare our method with recent network binarization methods, BinaryConnect and BinaryNets, and outperform these methods by large margins on ImageNet, more than 16% in top-1 accuracy. Our code is available at: http://allenai.org/plato/xnornet.

神经网络二进制通过将其权重和激活量化为1位来加速深层模型。但是，二进制神经网络（BNN）与其完整精确（FP）对应物之间仍然存在巨大的性能差距。由于早期作品中权重二进制引起的量化误差已减少，因此激活二进化成为进一步提高准确性的主要障碍。 BNN表征了独特而有趣的结构，其中二进制和潜在的fp激活存在于同一正向通行证中（\ textit {i.e。} $ \ text {binarize}（\ mathbf {a} _f {a} _f）= \ mathbf {a a} _b $） 。为了减轻从FP到二元激活的二进化操作引起的信息降解，我们在通过互信息（MI）最大化的镜头训练BNN时建立了一种新颖的对比学习框架。将MI作为指标引入，以衡量二进制和FP激活之间共享的信息，这有助于对比度学习。具体而言，通过从相同输入样品中拉出二进制和FP激活的正对，以及从不同样品中推动负面对（负面对数的数量可以大大），从而极大地增强了BNN的表示能力。这使下游任务不仅有益于分类，而且还受益于分类和深度估计，〜\ textit {etc}。实验结果表明，我们的方法可以作为现有最新二元方法的堆积模块实现NYUD-V2的能力。

通过移除昂贵的乘法操作并将连续权重量化成低比特离散值来减少计算复杂性，与传统的神经网络相比，这是快速且节能的低比特离散值。然而，现有的换档网络对重量初始化敏感，并且还产生由消失梯度和重量率冻结问题引起的降级性能。为了解决这些问题，我们提出了一种低点重新参数化，这是一种用于训练低位换档网络的新技术。我们的方法以符号稀疏偏移3倍的方式分解离散参数。以这种方式，它有效地学习了一个低比特网络，其权重动力学类似于全精密网络并对重量初始化不敏感。我们所提出的培训方法推动移位神经网络的界限，并以在想象中的前1个精度方面显示出3位换档网络。

Although weight and activation quantization is an effective approach for Deep Neural Network (DNN) compression and has a lot of potentials to increase inference speed leveraging bit-operations, there is still a noticeable gap in terms of prediction accuracy between the quantized model and the full-precision model. To address this gap, we propose to jointly train a quantized, bit-operation-compatible DNN and its associated quantizers, as opposed to using fixed, handcrafted quantization schemes such as uniform or logarithmic quantization. Our method for learning the quantizers applies to both network weights and activations with arbitrary-bit precision, and our quantizers are easy to train. The comprehensive experiments on CIFAR-10 and ImageNet datasets show that our method works consistently well for various network structures such as AlexNet, VGG-Net, GoogLeNet, ResNet, and DenseNet, surpassing previous quantization methods in terms of accuracy by an appreciable margin. Code available at https://github.com/Microsoft/LQ-Nets

二进制神经网络利用$标志$函数来二进制真实值，其非衍生属性不可避免地会在反向传播期间带来巨大的梯度错误。尽管已经提出了许多手工设计的软功能来近似梯度，但它们的机制尚不清楚，并且在二进制模型及其完整精确的对应物之间仍然存在巨大的性能差距。为了解决这个问题，我们建议将网络二进制作为二进制分类问题解决，并使用多层感知器（MLP）作为分类器。基于MLP的分类器理论上可以符合任何连续功能，并可以自适应地学习，以对网络进行二进制和反向流向梯度，而无需任何特定的软函数。通过这种观点，我们进一步证明，即使是简单的线性函数也可以胜过先前的复杂软函数。广泛的实验表明，所提出的方法在图像分类和人类姿势估计任务中产生令人惊讶的表现。具体而言，我们在ImageNet数据集上实现了Resnet-34的65.7％的TOP-1准确性，绝对提高了2.8％。在评估具有挑战性的Microsoft可可关键数据集时，提出的方法使二进制网络能够首次获得60.6的地图，并与一些完整的方法相当。

Low-rankness plays an important role in traditional machine learning, but is not so popular in deep learning. Most previous low-rank network compression methods compress the networks by approximating pre-trained models and re-training. However, the optimal solution in the Euclidean space may be quite different from the one in the low-rank manifold. A well-pre-trained model is not a good initialization for the model with low-rank constraints. Thus, the performance of a low-rank compressed network degrades significantly. Compared to other network compression methods such as pruning, low-rank methods attracts less attention in recent years. In this paper, we devise a new training method, low-rank projection with energy transfer (LRPET), that trains low-rank compressed networks from scratch and achieves competitive performance. First, we propose to alternately perform stochastic gradient descent training and projection onto the low-rank manifold. Compared to re-training on the compact model, this enables full utilization of model capacity since solution space is relaxed back to Euclidean space after projection. Second, the matrix energy (the sum of squares of singular values) reduction caused by projection is compensated by energy transfer. We uniformly transfer the energy of the pruned singular values to the remaining ones. We theoretically show that energy transfer eases the trend of gradient vanishing caused by projection. Third, we propose batch normalization (BN) rectification to cut off its effect on the optimal low-rank approximation of the weight matrix, which further improves the performance. Comprehensive experiments on CIFAR-10 and ImageNet have justified that our method is superior to other low-rank compression methods and also outperforms recent state-of-the-art pruning methods. Our code is available at https://github.com/BZQLin/LRPET.

二进制神经网络（BNNS）对现实世界中嵌入式设备显示出巨大的希望。作为实现强大BNN的关键步骤之一，规模因子计算在减少其实价对应物的性能差距方面起着至关重要的作用。然而，现有的BNN忽略了实价重量和尺度因子的固有双线关系，从而导致训练过程不足引起的亚最佳模型。为了解决这个问题，提出了复发性双线性优化，以通过将固有的双线性变量关联到背面传播过程中，以改善BNNS（RBONN）的学习过程。我们的工作是从双线性角度优化BNN的首次尝试。具体而言，我们采用经常​​性优化和密度 - 列表来依次回溯稀疏的实价过滤器，该过滤器将经过充分的训练并基于可控的学习过程达到其性能限制。我们获得了强大的rbonn，在各种模型和数据集上的最先进的BNN上表现出令人印象深刻的性能。特别是，在对象检测的任务下，rbonn具有出色的概括性能。我们的代码在https://github.com/stevetsui/rbonn上进行开源。

We introduce a method to train Quantized Neural Networks (QNNs) -neural networks with extremely low precision (e.g., 1-bit) weights and activations, at run-time. At traintime the quantized weights and activations are used for computing the parameter gradients. During the forward pass, QNNs drastically reduce memory size and accesses, and replace most arithmetic operations with bit-wise operations. As a result, power consumption is expected to be drastically reduced. We trained QNNs over the MNIST, CIFAR-10, SVHN and ImageNet datasets. The resulting QNNs achieve prediction accuracy comparable to their 32-bit counterparts. For example, our quantized version of AlexNet with 1-bit weights and 2-bit activations achieves 51% top-1 accuracy. Moreover, we quantize the parameter gradients to 6-bits as well which enables gradients computation using only bit-wise operation. Quantized recurrent neural networks were tested over the Penn Treebank dataset, and achieved comparable accuracy as their 32-bit counterparts using only 4-bits. Last but not least, we programmed a binary matrix multiplication GPU kernel with which it is possible to run our MNIST QNN 7 times faster than with an unoptimized GPU kernel, without suffering any loss in classification accuracy. The QNN code is available online.

While machine learning is traditionally a resource intensive task, embedded systems, autonomous navigation, and the vision of the Internet of Things fuel the interest in resource-efficient approaches. These approaches aim for a carefully chosen trade-off between performance and resource consumption in terms of computation and energy. The development of such approaches is among the major challenges in current machine learning research and key to ensure a smooth transition of machine learning technology from a scientific environment with virtually unlimited computing resources into everyday's applications. In this article, we provide an overview of the current state of the art of machine learning techniques facilitating these real-world requirements. In particular, we focus on deep neural networks (DNNs), the predominant machine learning models of the past decade. We give a comprehensive overview of the vast literature that can be mainly split into three non-mutually exclusive categories: (i) quantized neural networks, (ii) network pruning, and (iii) structural efficiency. These techniques can be applied during training or as post-processing, and they are widely used to reduce the computational demands in terms of memory footprint, inference speed, and energy efficiency. We also briefly discuss different concepts of embedded hardware for DNNs and their compatibility with machine learning techniques as well as potential for energy and latency reduction. We substantiate our discussion with experiments on well-known benchmark datasets using compression techniques (quantization, pruning) for a set of resource-constrained embedded systems, such as CPUs, GPUs and FPGAs. The obtained results highlight the difficulty of finding good trade-offs between resource efficiency and predictive performance.

Deploying convolutional neural networks (CNNs) on embedded devices is difficult due to the limited memory and computation resources. The redundancy in feature maps is an important characteristic of those successful CNNs, but has rarely been investigated in neural architecture design. This paper proposes a novel Ghost module to generate more feature maps from cheap operations. Based on a set of intrinsic feature maps, we apply a series of linear transformations with cheap cost to generate many ghost feature maps that could fully reveal information underlying intrinsic features. The proposed Ghost module can be taken as a plug-and-play component to upgrade existing convolutional neural networks. Ghost bottlenecks are designed to stack Ghost modules, and then the lightweight Ghost-Net can be easily established. Experiments conducted on benchmarks demonstrate that the proposed Ghost module is an impressive alternative of convolution layers in baseline models, and our GhostNet can achieve higher recognition performance (e.g. 75.7% top-1 accuracy) than MobileNetV3 with similar computational cost on the ImageNet ILSVRC-2012 classification dataset. Code is available at https: //github.com/huawei-noah/ghostnet.

用于压缩神经网络的非均匀量化策略通常实现的性能比其对应于对应物，即统一的策略，因为其优越的代表性能力。然而，许多非均匀量化方法在实现不均匀量化的权重/激活时忽略了复杂的投影过程，这在硬件部署中引起了不可忽略的时间和空间开销。在这项研究中，我们提出了非均匀致均匀的量化（N2UQ），一种方法，其能够保持非均匀方法的强表示能力，同时硬件友好且有效地作为模型推理的均匀量化。我们通过学习灵活的等距输入阈值来实现这一目标，以更好地拟合潜在的分布，同时将这些实值输入量化为等距输出电平。要使用可学习的输入阈值训练量化网络，我们将广义直通估计器（G-STE）介绍，用于难以应答的后向衍生计算W.r.t.阈值参数。此外，我们考虑熵保持正则化，以进一步降低重量量化的信息损失。即使在这种不利约束的施加均匀量化的重量和激活的情况下，我们的N2UQ也经历了最先进的非均匀量化方法，在想象中达到了0.7〜1.8％，展示了N2UQ设计的贡献。代码将公开可用。

最近，低精确的深度学习加速器（DLA）由于其在芯片区域和能源消耗方面的优势而变得流行，但是这些DLA上的低精确量化模型导致严重的准确性降解。达到高精度和高效推断的一种方法是在低精度DLA上部署高精度神经网络，这很少被研究。在本文中，我们提出了平行的低精确量化（PALQUANT）方法，该方法通过从头开始学习并行低精度表示来近似高精度计算。此外，我们提出了一个新型的循环洗牌模块，以增强平行低精度组之间的跨组信息通信。广泛的实验表明，PALQUANT的精度和推理速度既优于最先进的量化方法，例如，对于RESNET-18网络量化，PALQUANT可以获得0.52 \％的准确性和1.78 $ \ times $ speedup同时获得在最先进的2位加速器上的4位反片机上。代码可在\ url {https://github.com/huqinghao/palquant}中获得。

由于存储器和计算资源有限，部署在移动设备上的卷积神经网络（CNNS）是困难的。我们的目标是通过利用特征图中的冗余来设计包括CPU和GPU的异构设备的高效神经网络，这很少在神经结构设计中进行了研究。对于类似CPU的设备，我们提出了一种新颖的CPU高效的Ghost（C-Ghost）模块，以生成从廉价操作的更多特征映射。基于一组内在的特征映射，我们使用廉价的成本应用一系列线性变换，以生成许多幽灵特征图，可以完全揭示内在特征的信息。所提出的C-Ghost模块可以作为即插即用组件，以升级现有的卷积神经网络。 C-Ghost瓶颈旨在堆叠C-Ghost模块，然后可以轻松建立轻量级的C-Ghostnet。我们进一步考虑GPU设备的有效网络。在建筑阶段的情况下，不涉及太多的GPU效率（例如，深度明智的卷积），我们建议利用阶段明智的特征冗余来制定GPU高效的幽灵（G-GHOST）阶段结构。舞台中的特征被分成两个部分，其中使用具有较少输出通道的原始块处理第一部分，用于生成内在特征，另一个通过利用阶段明智的冗余来生成廉价的操作。在基准测试上进行的实验证明了所提出的C-Ghost模块和G-Ghost阶段的有效性。 C-Ghostnet和G-Ghostnet分别可以分别实现CPU和GPU的准确性和延迟的最佳权衡。代码可在https://github.com/huawei-noah/cv-backbones获得。

卷积神经网络（CNN）的量化是缓解CNN部署的计算负担，尤其是在低资源边缘设备上的常见方法。但是，对于神经网络所涉及的计算类型，固定点算术并不是自然的。在这项工作中，我们探索了使用基于PDE的观点和分析来改善量化CNN的方法。首先，我们利用总变化方法（电视）方法将边缘意识平滑应用于整个网络的特征图。这旨在减少值分布的异常值并促进零件恒定图，这更适合量化。其次，我们考虑用于图像分类的常见CNN的对称和稳定变体，以及用于图源分类的图形卷积网络（GCN）。我们通过几个实验证明，正向稳定性的性质保留了在不同量化速率下网络的作用。结果，稳定的量化网络的行为与非量化的网络相似，即使它们依赖于较少的参数。我们还发现，有时，稳定性甚至有助于提高准确性。对于敏感，资源受限，低功率或实时应用（例如自动驾驶），这些属性特别感兴趣。