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.

Pre-trained language models achieve superior performance, but they are computationally expensive due to their large size. Techniques such as pruning and knowledge distillation (KD) have been developed to reduce their size and latency. In most structural pruning methods, the pruning units, such as attention heads and feed-forward hidden dimensions, only span a small model structure space and limit the structures that the pruning algorithm can explore. In this work, we propose Gradient-based Intra-attention pruning (GRAIN), which inspects fine intra-attention structures, and allows different heads to have different sizes. Intra-attention pruning greatly expands the searching space of model structures and yields highly heterogeneous structures. We further propose structure regularization to encourage generating more regular structures, which achieves higher speedups than heterogeneous ones. We also integrate KD into the pruning process with a gradient separation strategy to reduce the interference of KD with the pruning process. GRAIN is evaluated on a variety of tasks. Results show that it notably outperforms other methods at the same or similar model size. Even under extreme compression where only $3\%$ weights in transformers remain, the pruned model is still competitive.

Deformable image registration, i.e., the task of aligning multiple images into one coordinate system by non-linear transformation, serves as an essential preprocessing step for neuroimaging data. Recent research on deformable image registration is mainly focused on improving the registration accuracy using multi-stage alignment methods, where the source image is repeatedly deformed in stages by a same neural network until it is well-aligned with the target image. Conventional methods for multi-stage registration can often blur the source image as the pixel/voxel values are repeatedly interpolated from the image generated by the previous stage. However, maintaining image quality such as sharpness during image registration is crucial to medical data analysis. In this paper, we study the problem of anti-blur deformable image registration and propose a novel solution, called Anti-Blur Network (ABN), for multi-stage image registration. Specifically, we use a pair of short-term registration and long-term memory networks to learn the nonlinear deformations at each stage, where the short-term registration network learns how to improve the registration accuracy incrementally and the long-term memory network combines all the previous deformations to allow an interpolation to perform on the raw image directly and preserve image sharpness. Extensive experiments on both natural and medical image datasets demonstrated that ABN can accurately register images while preserving their sharpness. Our code and data can be found at https://github.com/anonymous3214/ABN

The modern dynamic and heterogeneous network brings differential environments with respective state transition probability to agents, which leads to the local strategy trap problem of traditional federated reinforcement learning (FRL) based network optimization algorithm. To solve this problem, we propose a novel Differentiated Federated Reinforcement Learning (DFRL), which evolves the global policy model integration and local inference with the global policy model in traditional FRL to a collaborative learning process with parallel global trends learning and differential local policy model learning. In the DFRL, the local policy learning model is adaptively updated with the global trends model and local environment and achieves better differentiated adaptation. We evaluate the outperformance of the proposal compared with the state-of-the-art FRL in a classical CartPole game with heterogeneous environments. Furthermore, we implement the proposal in the heterogeneous Space-air-ground Integrated Network (SAGIN) for the classical traffic offloading problem in network. The simulation result shows that the proposal shows better global performance and fairness than baselines in terms of throughput, delay, and packet drop rate.

Many real-world problems are usually computationally costly and the objective functions evolve over time. Data-driven, a.k.a. surrogate-assisted, evolutionary optimization has been recognized as an effective approach for tackling expensive black-box optimization problems in a static environment whereas it has rarely been studied under dynamic environments. This paper proposes a simple but effective transfer learning framework to empower data-driven evolutionary optimization to solve dynamic optimization problems. Specifically, it applies a hierarchical multi-output Gaussian process to capture the correlation between data collected from different time steps with a linearly increased number of hyperparameters. Furthermore, an adaptive source task selection along with a bespoke warm staring initialization mechanisms are proposed to better leverage the knowledge extracted from previous optimization exercises. By doing so, the data-driven evolutionary optimization can jump start the optimization in the new environment with a strictly limited computational budget. Experiments on synthetic benchmark test problems and a real-world case study demonstrate the effectiveness of our proposed algorithm against nine state-of-the-art peer algorithms.

公平性是一个标准，重点是评估不同人口组的算法性能，它引起了自然语言处理，推荐系统和面部识别的关注。由于医学图像样本中有很多人口统计学属性，因此了解公平的概念，熟悉不公平的缓解技术，评估算法的公平程度并认识到医疗图像分析（媒体）中的公平问题中的挑战很重要。在本文中，我们首先给出了公平性的全面和精确的定义，然后通过在媒体中引入当前使用的技术中使用的技术。之后，我们列出了包含人口统计属性的公共医疗图像数据集，以促进公平研究并总结有关媒体公平性的当前算法。为了帮助更好地理解公平性，并引起人们对媒体中与公平性有关的问题的关注，进行了实验，比较公平性和数据失衡之间的差异，验证各种媒体任务中不公平的存在，尤其是在分类，细分和检测以及评估不公平缓解算法的有效性。最后，我们以媒体公平性的机会和挑战得出结论。

解决组合优化（CO）问题的传统求解器通常是由人类专家设计的。最近，人们对利用深度学习，尤其是深度强化学习的兴趣激增，自动为CO学习有效的求解器。由此产生的新范式称为神经组合优化（NCO）。但是，在经验或理论上，NCO的优势和缺点与其他方法的优势尚未得到很好的研究。在这项工作中，我们介绍了NCO求解器和替代求解器的全面比较研究。具体而言，将旅行推销员问题作为测试床问题，我们根据五个方面（即有效性，效率，稳定性，可扩展性和概括能力）评估求解器的性能。我们的结果表明，通常，NCO方法学到的求解器几乎在所有这些方面仍然没有传统求解器。前者的潜在好处将是在有足够的培训实例时，他们在小规模的问题实例上的卓越时间和能源效率。我们希望这项工作将有助于更好地理解NCO的优势和劣势，并提供全面的评估协议，以进一步对NCO进行针对其他方法的基准测试。

这项工作解决了中央机器学习问题的问题，即在分布（OOD）测试集上的性能降解问题。这个问题在基于医学成像的诊断系统中尤为明显，该系统似乎是准确的，但在新医院/数据集中进行测试时失败。最近的研究表明，该系统可能会学习快捷方式和非相关功能，而不是可推广的功能，即所谓的良好功能。我们假设对抗性训练可以消除快捷方式功能，而显着性训练可以滤除非相关功能。两者都是OOD测试集的性能降解的滋扰功能。因此，我们为深度神经网络制定了一种新颖的模型培训方案，以学习分类和/或检测任务的良好功能，以确保在OOD测试集上的概括性性能。实验结果定性和定量证明了我们使用基准CXR图像数据集在分类任务上的基准CXR图像数据集的出色性能。

Federated学习（FL）最近作为一种增强隐私的工具而受到了极大的关注，可以由多个参与者共同培训机器学习模型。FL的先前工作主要研究了如何在模型培训期间保护标签隐私。但是，FL中的模型评估也可能导致私人标签信息的潜在泄漏。在这项工作中，我们提出了一种评估算法，该算法可以准确计算使用FL中的标签差异隐私（DP）时，可以准确计算广泛使用的AUC（曲线下）度量。通过广泛的实验，我们显示我们的算法可以计算与地面真相相比的准确AUC。

人脑中的神经网络如何代表常识性知识，而完整的相关推理任务是神经科学，认知科学，心理学和人工智能的重要研究主题。尽管使用固定长度向量代表符号的传统人工神经网络在某些特定任务中取得了良好的表现，但它仍然是一个黑匣子，缺乏可解释性，远非人类对世界的看法。受神经科学中的祖母细胞假设的启发，这项工作调查了可以将编码和峰值定时依赖性可塑性（STDP）机制的人群整合到峰值神经网络的学习中，以及神经元的人群如何通过指导符号来指导符号在不同的神经元种群之间完成顺序触发。不同社区的神经元种群共同构成了整个常识知识图，形成了巨大的图形尖峰神经网络。此外，我们引入了奖励调节的峰值时间依赖性可塑性（R-STDP）机制，以模拟生物增强学习过程并相应地完成相关推理任务，比图形卷积人工神经网络实现了可比的准确性和更快的收敛速度。对于神经科学和认知科学领域，本文的工作为进一步探索人脑代表常识知识的方式提供了计算建模的基础。对于人工智能领域，本文通过构建常识性知识表示并推理具有固体生物学合理性的尖峰神经网络，指出了实现更健壮和可解释的神经网络的探索方向。