The number of international benchmarking competitions is steadily increasing in various fields of machine learning (ML) research and practice. So far, however, little is known about the common practice as well as bottlenecks faced by the community in tackling the research questions posed. To shed light on the status quo of algorithm development in the specific field of biomedical imaging analysis, we designed an international survey that was issued to all participants of challenges conducted in conjunction with the IEEE ISBI 2021 and MICCAI 2021 conferences (80 competitions in total). The survey covered participants' expertise and working environments, their chosen strategies, as well as algorithm characteristics. A median of 72% challenge participants took part in the survey. According to our results, knowledge exchange was the primary incentive (70%) for participation, while the reception of prize money played only a minor role (16%). While a median of 80 working hours was spent on method development, a large portion of participants stated that they did not have enough time for method development (32%). 25% perceived the infrastructure to be a bottleneck. Overall, 94% of all solutions were deep learning-based. Of these, 84% were based on standard architectures. 43% of the respondents reported that the data samples (e.g., images) were too large to be processed at once. This was most commonly addressed by patch-based training (69%), downsampling (37%), and solving 3D analysis tasks as a series of 2D tasks. K-fold cross-validation on the training set was performed by only 37% of the participants and only 50% of the participants performed ensembling based on multiple identical models (61%) or heterogeneous models (39%). 48% of the respondents applied postprocessing steps.

Cross-Entropy Method (CEM) is commonly used for planning in model-based reinforcement learning (MBRL) where a centralized approach is typically utilized to update the sampling distribution based on only the top-$k$ operation's results on samples. In this paper, we show that such a centralized approach makes CEM vulnerable to local optima, thus impairing its sample efficiency. To tackle this issue, we propose Decentralized CEM (DecentCEM), a simple but effective improvement over classical CEM, by using an ensemble of CEM instances running independently from one another, and each performing a local improvement of its own sampling distribution. We provide both theoretical and empirical analysis to demonstrate the effectiveness of this simple decentralized approach. We empirically show that, compared to the classical centralized approach using either a single or even a mixture of Gaussian distributions, our DecentCEM finds the global optimum much more consistently thus improves the sample efficiency. Furthermore, we plug in our DecentCEM in the planning problem of MBRL, and evaluate our approach in several continuous control environments, with comparison to the state-of-art CEM based MBRL approaches (PETS and POPLIN). Results show sample efficiency improvement by simply replacing the classical CEM module with our DecentCEM module, while only sacrificing a reasonable amount of computational cost. Lastly, we conduct ablation studies for more in-depth analysis. Code is available at https://github.com/vincentzhang/decentCEM

In classic reinforcement learning algorithms, agents make decisions at discrete and fixed time intervals. The physical duration between one decision and the next becomes a critical hyperparameter. When this duration is too short, the agent needs to make many decisions to achieve its goal, aggravating the problem's difficulty. But when this duration is too long, the agent becomes incapable of controlling the system. Physical systems, however, do not need a constant control frequency. For learning agents, it is desirable to operate with low frequency when possible and high frequency when necessary. We propose a framework called Continuous-Time Continuous-Options (CTCO), where the agent chooses options as sub-policies of variable durations. Such options are time-continuous and can interact with the system at any desired frequency providing a smooth change of actions. The empirical analysis shows that our algorithm is competitive w.r.t. other time-abstraction techniques, such as classic option learning and action repetition, and practically overcomes the difficult choice of the decision frequency.

Workloads in modern cloud data centers are becoming increasingly complex. The number of workloads running in cloud data centers has been growing exponentially for the last few years, and cloud service providers (CSP) have been supporting on-demand services in real-time. Realizing the growing complexity of cloud environment and cloud workloads, hardware vendors such as Intel and AMD are increasingly introducing cloud-specific workload acceleration features in their CPU platforms. These features are typically targeted towards popular and commonly-used cloud workloads. Nonetheless, uncommon, customer-specific workloads (unknown workloads), if their characteristics are different from common workloads (known workloads), may not realize the potential of the underlying platform. To address this problem of realizing the full potential of the underlying platform, we develop a machine learning based technique to characterize, profile and predict workloads running in the cloud environment. Experimental evaluation of our technique demonstrates good prediction performance. We also develop techniques to analyze the performance of the model in a standalone manner.

The explosive growth of dynamic and heterogeneous data traffic brings great challenges for 5G and beyond mobile networks. To enhance the network capacity and reliability, we propose a learning-based dynamic time-frequency division duplexing (D-TFDD) scheme that adaptively allocates the uplink and downlink time-frequency resources of base stations (BSs) to meet the asymmetric and heterogeneous traffic demands while alleviating the inter-cell interference. We formulate the problem as a decentralized partially observable Markov decision process (Dec-POMDP) that maximizes the long-term expected sum rate under the users' packet dropping ratio constraints. In order to jointly optimize the global resources in a decentralized manner, we propose a federated reinforcement learning (RL) algorithm named federated Wolpertinger deep deterministic policy gradient (FWDDPG) algorithm. The BSs decide their local time-frequency configurations through RL algorithms and achieve global training via exchanging local RL models with their neighbors under a decentralized federated learning framework. Specifically, to deal with the large-scale discrete action space of each BS, we adopt a DDPG-based algorithm to generate actions in a continuous space, and then utilize Wolpertinger policy to reduce the mapping errors from continuous action space back to discrete action space. Simulation results demonstrate the superiority of our proposed algorithm to benchmark algorithms with respect to system sum rate.

很少有人提出了几乎没有阶级的课程学习（FSCIL），目的是使深度学习系统能够逐步学习有限的数据。最近，一位先驱声称，通常使用的基于重播的课堂学习方法（CIL）是无效的，因此对于FSCIL而言并不是首选。如果真理，这对FSCIL领域产生了重大影响。在本文中，我们通过经验结果表明，采用数据重播非常有利。但是，存储和重播旧数据可能会导致隐私问题。为了解决此问题，我们或建议使用无数据重播，该重播可以通过发电机综合数据而无需访问真实数据。在观察知识蒸馏的不确定数据的有效性时，我们在发电机培训中强加了熵正则化，以鼓励更不确定的例子。此外，我们建议使用单速样标签重新标记生成的数据。这种修改使网络可以通过完全减少交叉渗透损失来学习，从而减轻了在常规知识蒸馏方法中平衡不同目标的问题。最后，我们对CIFAR-100，Miniimagenet和Cub-200展示了广泛的实验结果和分析，以证明我们提出的效果。

Fairness has been taken as a critical metric in machine learning models, which is considered as an important component of trustworthy machine learning. In this paper, we focus on obtaining fairness for popular link prediction tasks, which are measured by dyadic fairness. A novel pre-processing methodology is proposed to establish dyadic fairness through data repairing based on optimal transport theory. With the well-established theoretical connection between the dyadic fairness for graph link prediction and a conditional distribution alignment problem, the dyadic repairing scheme can be equivalently transformed into a conditional distribution alignment problem. Furthermore, an optimal transport-based dyadic fairness algorithm called DyadicOT is obtained by efficiently solving the alignment problem, satisfying flexibility and unambiguity requirements. The proposed DyadicOT algorithm shows superior results in obtaining fairness compared to other fairness methods on two benchmark graph datasets.

去耦时尚表示是指将空间和时间特征分解成尺寸无关的因素。尽管以前的基于RGB-D的运动识别方法通过紧密耦合的多模态时空表示来实现了有希望的性能，但由于紧密的时空缠绕的建模，它们仍然在小数据设置下遭受（i）优化困难;（ii）信息冗余通常包含与分类弱相关的大量边际信息; （iii）由晚期融合不足引起的多模态起峰型信息之间的低相互作用。为了缓解这些缺点，我们建议去除并循环基于RGB-D的运动识别的时空表示。具体而言，我们解开了学习时空表示的任务到3个子任务：（1）通过解耦的空间和时间建模网络学习高质量和维度独立特征。 （2）重新汇总解耦表示，以确定更强的时空依赖。 （3）引入跨型自适应后融合（CAPF）机制，用于从RGB-D数据捕获跨模态时空信息。这些新颖设计的无缝组合形成了强大的时空表示，而不是在四个公共运动数据集上的最先进的方法实现了更好的性能。我们的代码可在https://github.com/damo-cv/motionrgbd获得。

目的：开发和验证基于临床阴性ALN的早期乳腺癌（EBC）术后预测腋窝淋巴结（ALN）转移的深度学习（DL）的主要肿瘤活检签名。方法：从2010年5月到2020年5月，共注册了1,058名具有病理证实ALN状态的eBC患者。基于关注的多实例学习（AMIL）框架，建立了一种DL核心针活检（DL-CNB）模型利用DL特征预测ALN状态，该DL特征从两位病理学家注释的乳腺CNB样本的数字化全幻灯片（WSIS）的癌症区域提取。分析了准确性，灵敏度，特异性，接收器操作特征（ROC）曲线和ROC曲线（AUC）下的区域进行评估，评估我们的模型。结果：具有VGG16_BN的最佳性DL-CNB模型作为特征提取器实现了0.816的AUC（95％置信区间（CI）：0.758,0.865），以预测独立测试队列的阳性Aln转移。此外，我们的模型包含称为DL-CNB + C的临床数据，得到了0.831的最佳精度（95％CI：0.775,0.878），特别是对于50岁以下的患者（AUC：0.918,95％CI： 0.825,0.971）。 DL-CNB模型的解释表明，最高度预测ALN转移的顶部签名的特征在于包括密度（$ P $ 0.015），周长（$ P $ 0.009），循环（$ P $ = 0.010）和方向（$ p $ = 0.012）。结论：我们的研究提供了一种基于DL的基于DL的生物标志物在原发性肿瘤CNB上，以预先验证EBC患者的术前预测ALN的转移状态。

我们通过补充每个图像的弱点将内扫描（iOS）和牙科锥形电脑层析术（CBCT）图像集成到一个图像中的完全自动化方法。单独的牙科CBCT可能无法通过有限的图像分辨率和各种CBCT伪像（包括金属诱导的伪像）来描绘牙齿表面的精确细节。 iOS非常准确地扫描窄区域，但它在全拱扫描过程中产生累积缝合误差。该方法不仅要补偿具有iOS的CBCT衍生的牙齿表面的低质量，而且还要校正整个牙弓的IOS的累积拼接误差。此外，整合提供了一种图像中CBCT的IOS和齿根的牙龈结构。所提出的全自动方法包括四个部分; （i）iOS数据（TSIM-iOS）的单个牙齿分割和识别模块; （ii）CBCT数据（TSIM-CBCT）的个体齿分割和识别模块; （iii）IOS和CBCT之间的全球到局部牙齿登记; （iv）全拱ios的缝合纠错。实验结果表明，该方法分别达到了0.11mm和0.30mm的地标和表面距离误差。