为了提高性能，深度神经网络需要更深入或更广泛的网络结构，以涉及大量的计算和记忆成本。为了减轻此问题，自我知识蒸馏方法通过提炼模型本身的内部知识来规范模型。常规的自我知识蒸馏方法需要其他可训练的参数或取决于数据。在本文中，我们提出了一种使用辍学（SD-Dropout）的简单有效的自我知识蒸馏方法。 SD-Dropout通过辍学采样来提炼多个模型的后验分布。我们的方法不需要任何其他可训练的模块，不依赖数据，只需要简单的操作。此外，这种简单的方法可以很容易地与各种自我知识蒸馏方法结合在一起。我们提供了对远期和反向KL-Diverence在工作中的影响的理论和实验分析。对各种视觉任务（即图像分类，对象检测和分布移动）进行的广泛实验表明，所提出的方法可以有效地改善单个网络的概括。进一步的实验表明，所提出的方法还提高了校准性能，对抗性鲁棒性和分布外检测能力。

Knowledge distillation (KD) has gained a lot of attention in the field of model compression for edge devices thanks to its effectiveness in compressing large powerful networks into smaller lower-capacity models. Online distillation, in which both the teacher and the student are learning collaboratively, has also gained much interest due to its ability to improve on the performance of the networks involved. The Kullback-Leibler (KL) divergence ensures the proper knowledge transfer between the teacher and student. However, most online KD techniques present some bottlenecks under the network capacity gap. By cooperatively and simultaneously training, the models the KL distance becomes incapable of properly minimizing the teacher's and student's distributions. Alongside accuracy, critical edge device applications are in need of well-calibrated compact networks. Confidence calibration provides a sensible way of getting trustworthy predictions. We propose BD-KD: Balancing of Divergences for online Knowledge Distillation. We show that adaptively balancing between the reverse and forward divergences shifts the focus of the training strategy to the compact student network without limiting the teacher network's learning process. We demonstrate that, by performing this balancing design at the level of the student distillation loss, we improve upon both performance accuracy and calibration of the compact student network. We conducted extensive experiments using a variety of network architectures and show improvements on multiple datasets including CIFAR-10, CIFAR-100, Tiny-ImageNet, and ImageNet. We illustrate the effectiveness of our approach through comprehensive comparisons and ablations with current state-of-the-art online and offline KD techniques.

与常规知识蒸馏（KD）不同，自我KD允许网络在没有额外网络的任何指导的情况下向自身学习知识。本文提议从图像混合物（Mixskd）执行自我KD，将这两种技术集成到统一的框架中。 Mixskd相互蒸馏以图形和概率分布在随机的原始图像和它们的混合图像之间以有意义的方式。因此，它通过对混合图像进行监督信号进行建模来指导网络学习跨图像知识。此外，我们通过汇总多阶段功能图来构建一个自学老师网络，以提供软标签以监督骨干分类器，从而进一步提高自我增强的功效。图像分类和转移学习到对象检测和语义分割的实验表明，混合物KD优于其他最先进的自我KD和数据增强方法。该代码可在https://github.com/winycg/self-kd-lib上找到。

Knowledge distillation aims at transferring knowledge acquired in one model (a teacher) to another model (a student) that is typically smaller. Previous approaches can be expressed as a form of training the student to mimic output activations of individual data examples represented by the teacher. We introduce a novel approach, dubbed relational knowledge distillation (RKD), that transfers mutual relations of data examples instead. For concrete realizations of RKD, we propose distance-wise and angle-wise distillation losses that penalize structural differences in relations. Experiments conducted on different tasks show that the proposed method improves educated student models with a significant margin. In particular for metric learning, it allows students to outperform their teachers' performance, achieving the state of the arts on standard benchmark datasets.

知识蒸馏是通过知识转移模型压缩的有效稳定的方法。传统知识蒸馏（KD）是将来自大型和训练有素的教师网络的知识转移到小型学生网络，这是一种单向过程。最近，已经提出了深度相互学习（DML）来帮助学生网络协同和同时学习。然而，据我们所知，KD和DML从未在统一的框架中共同探索，以解决知识蒸馏问题。在本文中，我们调查教师模型在KD中支持更值得信赖的监督信号，而学生则在DML中捕获教师的类似行为。基于这些观察，我们首先建议将KD与DML联合在统一的框架中。此外，我们提出了一个半球知识蒸馏（SOKD）方法，有效提高了学生和教师的表现。在这种方法中，我们在DML中介绍了同伴教学培训时尚，以缓解学生的模仿困难，并利用KD训练有素的教师提供的监督信号。此外，我们还显示我们的框架可以轻松扩展到基于功能的蒸馏方法。在CiFAR-100和Imagenet数据集上的广泛实验证明了所提出的方法实现了最先进的性能。

知识蒸馏（KD）是一个有效的框架，旨在将有意义的信息从大型老师转移到较小的学生。通常，KD通常涉及如何定义和转移知识。以前的KD方法通常着重于挖掘各种形式的知识，例如功能地图和精致信息。但是，知识源自主要监督任务，因此是高度特定于任务的。在自我监督的代表学习的最新成功中，我们提出了一项辅助自我实施的增强任务，以指导网络学习更多有意义的功能。因此，我们可以从KD的这项任务中得出软性自我实施的增强分布作为更丰富的黑暗知识。与以前的知识不同，此分布编码从监督和自我监督的特征学习中编码联合知识。除了知识探索之外，我们建议在各个隐藏层上附加几个辅助分支，以充分利用分层特征图。每个辅助分支都被指导学习自学的增强任务，并将这种分布从教师到学生提炼。总体而言，我们称我们的KD方法为等级自我实施的增强知识蒸馏（HSSAKD）。标准图像分类的实验表明，离线和在线HSSAKD都在KD领域达到了最先进的表现。对象检测的进一步转移实验进一步验证了HSSAKD可以指导网络学习更好的功能。该代码可在https://github.com/winycg/hsakd上找到。

知识蒸馏已成为获得紧凑又有效模型的重要方法。为实现这一目标，培训小型学生模型以利用大型训练有素的教师模型的知识。然而，由于教师和学生之间的能力差距，学生的表现很难达到老师的水平。关于这个问题，现有方法建议通过代理方式减少教师知识的难度。我们认为这些基于代理的方法忽视了教师的知识损失，这可能导致学生遇到容量瓶颈。在本文中，我们从新的角度来缓解能力差距问题，以避免知识损失的目的。我们建议通过对抗性协作学习建立一个更有力的学生，而不是牺牲教师的知识。为此，我们进一步提出了一种逆势协作知识蒸馏（ACKD）方法，有效提高了知识蒸馏的性能。具体来说，我们用多个辅助学习者构建学生模型。同时，我们设计了对抗的对抗性协作模块（ACM），引入注意机制和对抗的学习，以提高学生的能力。四个分类任务的广泛实验显示了拟议的Ackd的优越性。

Most existing distillation methods ignore the flexible role of the temperature in the loss function and fix it as a hyper-parameter that can be decided by an inefficient grid search. In general, the temperature controls the discrepancy between two distributions and can faithfully determine the difficulty level of the distillation task. Keeping a constant temperature, i.e., a fixed level of task difficulty, is usually sub-optimal for a growing student during its progressive learning stages. In this paper, we propose a simple curriculum-based technique, termed Curriculum Temperature for Knowledge Distillation (CTKD), which controls the task difficulty level during the student's learning career through a dynamic and learnable temperature. Specifically, following an easy-to-hard curriculum, we gradually increase the distillation loss w.r.t. the temperature, leading to increased distillation difficulty in an adversarial manner. As an easy-to-use plug-in technique, CTKD can be seamlessly integrated into existing knowledge distillation frameworks and brings general improvements at a negligible additional computation cost. Extensive experiments on CIFAR-100, ImageNet-2012, and MS-COCO demonstrate the effectiveness of our method. Our code is available at https://github.com/zhengli97/CTKD.

无教师的在线知识蒸馏（KD）旨在培训多个学生模型的合奏，并彼此提炼知识。尽管现有的在线KD方法实现了理想的性能，但它们通常专注于阶级概率作为核心知识类型，而忽略了宝贵的特征代表性信息。我们为在线KD提供了一个相互的对比学习（MCL）框架。 MCL的核心思想是以在线方式进行对比分布的相互交互和对比度分布的转移。我们的MCL可以汇总跨网络嵌入信息，并最大化两个网络之间的相互信息的下限。这使每个网络能够从他人那里学习额外的对比知识，从而提供更好的特征表示形式，从而提高视觉识别任务的性能。除最后一层外，我们还将MCL扩展到辅助特征细化模块辅助的几个中间层。这进一步增强了在线KD的表示能力。关于图像分类和转移学习到视觉识别任务的实验表明，MCL可以针对最新的在线KD方法带来一致的性能提高。优势表明，MCL可以指导网络生成更好的特征表示。我们的代码可在https://github.com/winycg/mcl上公开获取。

最近对知识蒸馏的研究发现，组合来自多位教师或学生的“黑暗知识”是有助于为培训创造更好的软目标，但以更大的计算和/或参数的成本为本。在这项工作中，我们通过在同一批量中传播和集合其他样本的知识来提供批处理知识合奏（烘焙）以生产用于锚固图像的精细柔软目标。具体地，对于每个感兴趣的样本，根据采样间的亲和力加权知识的传播，其与当前网络一起估计。然后可以集合传播的知识以形成更好的蒸馏靶。通过这种方式，我们的烘焙框架只通过单个网络跨多个样本进行在线知识。与现有知识合并方法相比，它需要最小的计算和内存开销。广泛的实验表明，轻质但有效的烘烤始终如一地提升多个数据集上各种架构的分类性能，例如，在想象网上的显着+ 0.7％的VINE-T的增益，只有+ 1.5％计算开销和零附加参数。烘焙不仅改善了Vanilla基线，还超越了所有基准的单一网络最先进。

自我介绍在训练过程中利用自身的非均匀软监管，并在没有任何运行时成本的情况下提高性能。但是，在训练过程中的开销经常被忽略，但是在巨型模型的时代，培训期间的时间和记忆开销越来越重要。本文提出了一种名为ZIPF标签平滑（ZIPF的LS）的有效自我验证方法，该方法使用网络的直立预测来生成软监管，该软监管在不使用任何对比样本或辅助参数的情况下符合ZIPF分布。我们的想法来自经验观察，即当对网络进行适当训练时，在按样品的大小和平均分类后，应遵循分布的分布，让人联想到ZIPF的自然语言频率统计信息，这是在按样品中的大小和平均值进行排序之后进行的。 。通过在样本级别和整个培训期内强制执行此属性，我们发现预测准确性可以大大提高。使用INAT21细粒分类数据集上的RESNET50，与香草基线相比，我们的技术获得了 +3.61％的准确性增长，而与先前的标签平滑或自我验证策略相比，增益增加了0.88％。该实现可在https://github.com/megvii-research/zipfls上公开获得。

知识蒸馏是从重型网络（教师）到小型网络（学生）的有效转移，以提高学生的表现。自我知识蒸馏是知识蒸馏的一种特殊情况，已提出在保持学生表现的同时删除大型教师网络培训过程。本文通过暹罗代表学习介绍了一种新型的自我知识蒸馏方法，该方法最大程度地减少了给定样本的两个不同观点的两个表示矢量之间的差异。我们提出的方法SKD-SRL使用了软标签蒸馏和表示向量的相似性。因此，SKD-SRL可以在同一数据点的各种视图中生成更一致的预测和表示。我们的基准已在各种标准数据集上进行了评估。实验结果表明，与现有的监督学习和知识蒸馏方法相比，SKD-SRL显着提高了准确性。

One of the most efficient methods for model compression is hint distillation, where the student model is injected with information (hints) from several different layers of the teacher model. Although the selection of hint points can drastically alter the compression performance, conventional distillation approaches overlook this fact and use the same hint points as in the early studies. Therefore, we propose a clustering based hint selection methodology, where the layers of teacher model are clustered with respect to several metrics and the cluster centers are used as the hint points. Our method is applicable for any student network, once it is applied on a chosen teacher network. The proposed approach is validated in CIFAR-100 and ImageNet datasets, using various teacher-student pairs and numerous hint distillation methods. Our results show that hint points selected by our algorithm results in superior compression performance compared to state-of-the-art knowledge distillation algorithms on the same student models and datasets.

Unlike existing knowledge distillation methods focus on the baseline settings, where the teacher models and training strategies are not that strong and competing as state-of-the-art approaches, this paper presents a method dubbed DIST to distill better from a stronger teacher. We empirically find that the discrepancy of predictions between the student and a stronger teacher may tend to be fairly severer. As a result, the exact match of predictions in KL divergence would disturb the training and make existing methods perform poorly. In this paper, we show that simply preserving the relations between the predictions of teacher and student would suffice, and propose a correlation-based loss to capture the intrinsic inter-class relations from the teacher explicitly. Besides, considering that different instances have different semantic similarities to each class, we also extend this relational match to the intra-class level. Our method is simple yet practical, and extensive experiments demonstrate that it adapts well to various architectures, model sizes and training strategies, and can achieve state-of-the-art performance consistently on image classification, object detection, and semantic segmentation tasks. Code is available at: https://github.com/hunto/DIST_KD .

知识蒸馏通常涉及如何有效地定义和转移知识从教师到学生。尽管最近的自我监督的对比知识取得了最佳表现，但迫使网络学习此类知识可能会损害对原始班级识别任务的表示。因此，我们采用替代性的自我监督的增强任务来指导网络学习原始识别任务和自我监督的辅助任务的共同分布。它被证明是一种更丰富的知识，可以提高表示能力而不会失去正常的分类能力。此外，以前的方法仅在最终层之间传递概率知识是不完整的。我们建议将几个辅助分类器附加到层次中间特征图中，以生成多样化的自我监督知识，并执行一对一的转移以彻底教授学生网络。我们的方法显着超过了先前的SOTA SSKD，CIFAR-100的平均改善为2.56 \％，并且在广泛使用的网络对上的Imagenet上有0.77 \％的提高。代码可在https://github.com/winycg/hsakd上找到。

随着AI芯片（例如GPU，TPU和NPU）的改进以及物联网（IOT）的快速发展，一些强大的深神经网络（DNN）通常由数百万甚至数亿个参数组成，这些参数是可能不适合直接部署在低计算和低容量单元（例如边缘设备）上。最近，知识蒸馏（KD）被认为是模型压缩的有效方法之一，以减少模型参数。 KD的主要概念是从大型模型（即教师模型）的特征图中提取有用的信息，以引用成功训练一个小型模型（即学生模型），该模型大小比老师小得多。尽管已经提出了许多基于KD的方法来利用教师模型中中间层的特征图中的信息，但是，它们中的大多数并未考虑教师模型和学生模型之间的特征图的相似性，这可能让学生模型学习无用的信息。受到注意机制的启发，我们提出了一种新颖的KD方法，称为代表教师钥匙（RTK），该方法不仅考虑了特征地图的相似性，而且还会过滤掉无用的信息以提高目标学生模型的性能。在实验中，我们使用多个骨干网络（例如Resnet和wideresnet）和数据集（例如CIFAR10，CIFAR100，SVHN和CINIC10）验证了我们提出的方法。结果表明，我们提出的RTK可以有效地提高基于注意的KD方法的分类精度。

Recently, large-scale pre-trained models have shown their advantages in many tasks. However, due to the huge computational complexity and storage requirements, it is challenging to apply the large-scale model to real scenes. A common solution is knowledge distillation which regards the large-scale model as a teacher model and helps to train a small student model to obtain a competitive performance. Cross-task Knowledge distillation expands the application scenarios of the large-scale pre-trained model. Existing knowledge distillation works focus on directly mimicking the final prediction or the intermediate layers of the teacher model, which represent the global-level characteristics and are task-specific. To alleviate the constraint of different label spaces, capturing invariant intrinsic local object characteristics (such as the shape characteristics of the leg and tail of the cattle and horse) plays a key role. Considering the complexity and variability of real scene tasks, we propose a Prototype-guided Cross-task Knowledge Distillation (ProC-KD) approach to transfer the intrinsic local-level object knowledge of a large-scale teacher network to various task scenarios. First, to better transfer the generalized knowledge in the teacher model in cross-task scenarios, we propose a prototype learning module to learn from the essential feature representation of objects in the teacher model. Secondly, for diverse downstream tasks, we propose a task-adaptive feature augmentation module to enhance the features of the student model with the learned generalization prototype features and guide the training of the student model to improve its generalization ability. The experimental results on various visual tasks demonstrate the effectiveness of our approach for large-scale model cross-task knowledge distillation scenes.

深度神经网络易于对自然投入的离前事实制作，小而难以察觉的变化影响。对这些实例的最有效的防御机制是对逆脉训练在训练期间通过迭代最大化的损失来构建对抗性实例。然后训练该模型以最小化这些构建的实施例的损失。此最小最大优化需要更多数据，更大的容量模型和额外的计算资源。它还降低了模型的标准泛化性能。我们可以更有效地实现鲁棒性吗？在这项工作中，我们从知识转移的角度探讨了这个问题。首先，我们理论上展示了在混合增强的帮助下将鲁棒性从对接地训练的教师模型到学生模型的可转换性。其次，我们提出了一种新颖的鲁棒性转移方法，称为基于混合的激活信道图（MixacM）转移。 MixacM通过匹配未在没有昂贵的对抗扰动的匹配生成的激活频道地图将强大的教师转移到学生的鲁棒性。最后，对多个数据集的广泛实验和不同的学习情景显示我们的方法可以转移鲁棒性，同时还改善自然图像的概括。

Despite the fact that deep neural networks are powerful models and achieve appealing results on many tasks, they are too large to be deployed on edge devices like smartphones or embedded sensor nodes. There have been efforts to compress these networks, and a popular method is knowledge distillation, where a large (teacher) pre-trained network is used to train a smaller (student) network. However, in this paper, we show that the student network performance degrades when the gap between student and teacher is large. Given a fixed student network, one cannot employ an arbitrarily large teacher, or in other words, a teacher can effectively transfer its knowledge to students up to a certain size, not smaller. To alleviate this shortcoming, we introduce multi-step knowledge distillation, which employs an intermediate-sized network (teacher assistant) to bridge the gap between the student and the teacher. Moreover, we study the effect of teacher assistant size and extend the framework to multi-step distillation. Theoretical analysis and extensive experiments on CIFAR-10,100 and ImageNet datasets and on CNN and ResNet architectures substantiate the effectiveness of our proposed approach.

机器学习中的知识蒸馏是将知识从名为教师的大型模型转移到一个名为“学生”的较小模型的过程。知识蒸馏是将大型网络（教师）压缩到较小网络（学生）的技术之一，该网络可以部署在手机等小型设备中。当教师和学生之间的网络规模差距增加时，学生网络的表现就会下降。为了解决这个问题，在教师模型和名为助教模型的学生模型之间采用了中间模型，这反过来弥补了教师与学生之间的差距。在这项研究中，我们已经表明，使用多个助教模型，可以进一步改进学生模型（较小的模型）。我们使用加权集合学习将这些多个助教模型组合在一起，我们使用了差异评估优化算法来生成权重值。