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.

The success of deep learning heavily relies on large-scale data with comprehensive labels, which is more expensive and time-consuming to fetch in 3D compared to 2D images or natural languages. This promotes the potential of utilizing models pretrained with data more than 3D as teachers for cross-modal knowledge transferring. In this paper, we revisit masked modeling in a unified fashion of knowledge distillation, and we show that foundational Transformers pretrained with 2D images or natural languages can help self-supervised 3D representation learning through training Autoencoders as Cross-Modal Teachers (ACT). The pretrained Transformers are transferred as cross-modal 3D teachers using discrete variational autoencoding self-supervision, during which the Transformers are frozen with prompt tuning for better knowledge inheritance. The latent features encoded by the 3D teachers are used as the target of masked point modeling, wherein the dark knowledge is distilled to the 3D Transformer students as foundational geometry understanding. Our ACT pretrained 3D learner achieves state-of-the-art generalization capacity across various downstream benchmarks, e.g., 88.21% overall accuracy on ScanObjectNN. Codes will be released at https://github.com/RunpeiDong/ACT.

Today, recommender systems have played an increasingly important role in shaping our experiences of digital environments and social interactions. However, as recommender systems become ubiquitous in our society, recent years have also witnessed significant fairness concerns for recommender systems. Specifically, studies have shown that recommender systems may inherit or even amplify biases from historical data, and as a result, provide unfair recommendations. To address fairness risks in recommender systems, most of the previous approaches to date are focused on modifying either the existing training data samples or the deployed recommender algorithms, but unfortunately with limited degrees of success. In this paper, we propose a new approach called fair recommendation with optimized antidote data (FairRoad), which aims to improve the fairness performances of recommender systems through the construction of a small and carefully crafted antidote dataset. Toward this end, we formulate our antidote data generation task as a mathematical optimization problem, which minimizes the unfairness of the targeted recommender systems while not disrupting the deployed recommendation algorithms. Extensive experiments show that our proposed antidote data generation algorithm significantly improve the fairness of recommender systems with a small amounts of antidote data.

The security of artificial intelligence (AI) is an important research area towards safe, reliable, and trustworthy AI systems. To accelerate the research on AI security, the Artificial Intelligence Security Competition (AISC) was organized by the Zhongguancun Laboratory, China Industrial Control Systems Cyber Emergency Response Team, Institute for Artificial Intelligence, Tsinghua University, and RealAI as part of the Zhongguancun International Frontier Technology Innovation Competition (https://www.zgc-aisc.com/en). The competition consists of three tracks, including Deepfake Security Competition, Autonomous Driving Security Competition, and Face Recognition Security Competition. This report will introduce the competition rules of these three tracks and the solutions of top-ranking teams in each track.

Existing object detection methods are bounded in a fixed-set vocabulary by costly labeled data. When dealing with novel categories, the model has to be retrained with more bounding box annotations. Natural language supervision is an attractive alternative for its annotation-free attributes and broader object concepts. However, learning open-vocabulary object detection from language is challenging since image-text pairs do not contain fine-grained object-language alignments. Previous solutions rely on either expensive grounding annotations or distilling classification-oriented vision models. In this paper, we propose a novel open-vocabulary object detection framework directly learning from image-text pair data. We formulate object-language alignment as a set matching problem between a set of image region features and a set of word embeddings. It enables us to train an open-vocabulary object detector on image-text pairs in a much simple and effective way. Extensive experiments on two benchmark datasets, COCO and LVIS, demonstrate our superior performance over the competing approaches on novel categories, e.g. achieving 32.0% mAP on COCO and 21.7% mask mAP on LVIS. Code is available at: https://github.com/clin1223/VLDet.

Federated learning (FL) is a collaborative machine learning framework that requires different clients (e.g., Internet of Things devices) to participate in the machine learning model training process by training and uploading their local models to an FL server in each global iteration. Upon receiving the local models from all the clients, the FL server generates a global model by aggregating the received local models. This traditional FL process may suffer from the straggler problem in heterogeneous client settings, where the FL server has to wait for slow clients to upload their local models in each global iteration, thus increasing the overall training time. One of the solutions is to set up a deadline and only the clients that can upload their local models before the deadline would be selected in the FL process. This solution may lead to a slow convergence rate and global model overfitting issues due to the limited client selection. In this paper, we propose the Latency awarE Semi-synchronous client Selection and mOdel aggregation for federated learNing (LESSON) method that allows all the clients to participate in the whole FL process but with different frequencies. That is, faster clients would be scheduled to upload their models more frequently than slow clients, thus resolving the straggler problem and accelerating the convergence speed, while avoiding model overfitting. Also, LESSON is capable of adjusting the tradeoff between the model accuracy and convergence rate by varying the deadline. Extensive simulations have been conducted to compare the performance of LESSON with the other two baseline methods, i.e., FedAvg and FedCS. The simulation results demonstrate that LESSON achieves faster convergence speed than FedAvg and FedCS, and higher model accuracy than FedCS.

神经辐射场（NERF）已成功用于场景表示。最近的工作还使用基于NERF的环境表示形式开发了机器人导航和操纵系统。由于对象定位是许多机器人应用的基础，因此进一步释放了机器人系统中NERF的潜力，我们研究了NERF场景中的对象定位。我们提出了一个基于变压器的框架NERF-LOC，以在NERF场景中提取3D边界对象框。 Nerf-Loc将预先训练的NERF模型和相机视图作为输入，并产生标记为3D边界对象的框作为输出。具体来说，我们设计了一对平行的变压器编码器分支，即粗流和细流，以编码目标对象的上下文和详细信息。然后将编码的功能与注意层融合在一起，以减轻准确对象定位的歧义。我们已经将我们的方法与基于传统变压器的方法进行了比较，我们的方法可以实现更好的性能。此外，我们还提出了第一个基于NERF样品的对象定位基准Nerflocbench。

现有的假音频检测系统通常依靠专家经验来设计声学功能或手动设计网络结构的超参数。但是，人工调整参数可能会对结果产生相对明显的影响。几乎不可能手动设置最佳参数集。因此，本文提出了一种完全自动化的终端伪造音频检测方法。我们首先使用WAV2VEC预训练模型来获得语音的高级表示。此外，对于网络结构，我们使用了名为Light-Darts的可区分体系结构搜索（飞镖）的修改版本。它学习了深厚的语音表示，同时自动学习和优化包括卷积操作和残留块组成的复杂神经结构。 ASVSPOOF 2019 LA数据集的实验结果表明，我们提出的系统达到的错误率（EER）为1.08％，这表现优于最先进的单个系统。

在混合完成的多任务，多域和多模式数据上进行预训练仍然是视力感知预训练的开放挑战。在本文中，我们提出了GPPF，这是一个普遍的感知预训练框架，预先培训任务级的动态网络，该网络是由在标签的多任务和多域数据集上的各层知识“乐高”组成的。通过检查人类在复杂环境中学习的先天能力，我们识别并将三个关键要素转移到深网上：（1）同时暴露于每个批次中的各种交叉任务和跨域信息。 （2）由知识共享驱动的单独的乐高单元中的分区知识存储。 （3）用于训练和下游任务的乐高单元子集的稀疏激活。值得注意的是，由于其在输入形状，损失功能，输出格式，数据分布等方面的差异，不同视觉任务的联合培训是不平凡的。因此，我们创新地开发了插件的多任务培训算法，该培训算法是支持单个迭代多个任务（SIMT）同时培训。 Simt用大型多任务多任务数据集为预训练的基础奠定了基础，并且被证明对于我们的GPPF实验中的稳定培训至关重要。令人兴奋的是，详尽的实验表明，我们的GPPF-R50型号在GPPF-15M中的8个预训练预培训任务的强大基线上取得了显着改善，并在22个下游任务中收获了一系列SOTA，并具有相似的计算预算。我们还验证了GPPF对SOTA视觉变压器的概括能力，并具有一致的改进。这些可靠的实验结果充分证明了我们新颖的GPPF框架提供的有效的知识学习，存储，共享和转移。

由于对个人数据隐私的不断增长和当地客户的迅速增长的数据量，Federated Learnated（FL）的动机已成为新的机器学习设置。 FL系统由中央参数服务器和多个本地客户端组成。它将数据保留在本地客户端，并通过共享本地学到的模型参数来学习集中式模型。不需要共享本地数据，并且可以很好地保护隐私。然而，由于它是模型而不是共享的原始数据，因此系统可以暴露于恶意客户端发起的中毒模型攻击。此外，由于服务器上没有本地客户端数据，因此确定恶意客户端是一项挑战。此外，仍然可以使用上载模型估算客户本地数据，从而导致隐私披露。在这项工作中，我们首先提出了一个基于模型更新的联合平均算法，以防御拜占庭式攻击，例如加性噪声攻击和弹药攻击。提出了单个客户模型初始化方法，以通过隐藏各个本地机器学习模型来提供进一步的隐私保护。在结合这两个方案时，隐私和安全性都可以有效地增强。当没有攻击时，提出的方案被证明在非IID数据分布下实验会收敛。在拜占庭式攻击下，提议的方案的表现要比基于经典模型的FedAvg算法要好得多。