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.
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对比度学习是视觉表示学习最成功的方法之一,可以通过在学习的表示上共同执行聚类来进一步提高其性能。但是,现有的联合聚类和对比度学习的方法在长尾数据分布上表现不佳,因为多数班级压倒了少数群体的损失,从而阻止了学习有意义的表示形式。由此激励,我们通过适应偏见的对比损失,以避免群集中的少数群体类别的不平衡数据集来开发一种新颖的联合聚类和对比度学习框架。我们表明,我们提出的修改后的对比损失和分歧聚类损失可改善多个数据集和学习任务的性能。源代码可从https://anonymon.4open.science/r/ssl-debiased-clustering获得
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从积极和未标记的(PU)数据中学习是一种设置,学习者只能访问正面和未标记的样本,而没有关于负面示例的信息。这种PU环境在各种任务中非常重要,例如医学诊断,社交网络分析,金融市场分析和知识基础完成,这些任务也往往本质上是不平衡的,即大多数示例实际上是负面的。但是,大多数现有的PU学习方法仅考虑人工平衡的数据集,目前尚不清楚它们在不平衡和长尾数据分布的现实情况下的表现如何。本文提议通过强大而有效的自我监督预处理来应对这一挑战。但是,培训传统的自我监督学习方法使用高度不平衡的PU分布需要更好的重新重新制定。在本文中,我们提出\ textit {Impulses},这是\ usewanced {im}平衡\下划线{p} osive \ unesive \ usepline {u} nlabeLed \ underline {l}的统一表示的学习框架{p}。 \下划线{s}削弱了debiase预训练。 Impulses使用大规模无监督学习的通用组合以及对比度损失和额外重新持续的PU损失的一般组合。我们在多个数据集上进行了不同的实验,以表明Impuls能够使先前最新的错误率减半,即使与先前给出的真实先验的方法相比。此外,即使在无关的数据集上进行了预处理,我们的方法也表现出对事先错误指定和卓越性能的鲁棒性。我们预计,这种稳健性和效率将使从业者更容易在其他感兴趣的PU数据集上获得出色的结果。源代码可在\ url {https://github.com/jschweisthal/impulses}中获得
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The ability to estimate epistemic uncertainty is often crucial when deploying machine learning in the real world, but modern methods often produce overconfident, uncalibrated uncertainty predictions. A common approach to quantify epistemic uncertainty, usable across a wide class of prediction models, is to train a model ensemble. In a naive implementation, the ensemble approach has high computational cost and high memory demand. This challenges in particular modern deep learning, where even a single deep network is already demanding in terms of compute and memory, and has given rise to a number of attempts to emulate the model ensemble without actually instantiating separate ensemble members. We introduce FiLM-Ensemble, a deep, implicit ensemble method based on the concept of Feature-wise Linear Modulation (FiLM). That technique was originally developed for multi-task learning, with the aim of decoupling different tasks. We show that the idea can be extended to uncertainty quantification: by modulating the network activations of a single deep network with FiLM, one obtains a model ensemble with high diversity, and consequently well-calibrated estimates of epistemic uncertainty, with low computational overhead in comparison. Empirically, FiLM-Ensemble outperforms other implicit ensemble methods, and it and comes very close to the upper bound of an explicit ensemble of networks (sometimes even beating it), at a fraction of the memory cost.
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积极的未标记(PU)学习旨在仅从积极和未标记的培训数据中学习二进制分类器。最近的方法通过发展无偏的损失功能通过对成本敏感的学习解决了这一问题,后来通过迭代伪标记解决方案改善了其性能。但是,这样的两步程序容易受到错误估计的伪标签的影响,因为在以后的错误预测训练新模型时,在以后的迭代中传播了错误。为了防止这种确认偏见,我们提出PUUPL是PU学习的新型损失不足的训练程序,该程序将认知不确定性纳入伪标签选择中。通过使用基于低确定性预测的神经网络的合奏并分配伪标记,我们表明PUUPL提高了伪标签的可靠性,提高了我们方法的预测性能,并导致了新的最先进的结果在自我训练中进行PU学习。通过广泛的实验,我们显示了方法对不同数据集,模式和学习任务的有效性,以及改进的校准,对先前拼写错误的稳健性,偏见的正数据和不平衡数据集。
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使用超越欧几里德距离的神经网络,深入的Bregman分歧测量数据点的分歧,并且能够捕获分布的发散。在本文中,我们提出了深深的布利曼对视觉表现的对比学习的分歧,我们的目标是通过基于功能Bregman分歧培训额外的网络来提高自我监督学习中使用的对比损失。与完全基于单点之间的分歧的传统对比学学习方法相比,我们的框架可以捕获分布之间的发散,这提高了学习表示的质量。我们展示了传统的对比损失和我们提出的分歧损失优于基线的结合,并且最先前的自我监督和半监督学习的大多数方法在多个分类和对象检测任务和数据集中。此外,学习的陈述在转移到其他数据集和任务时概括了良好。源代码和我们的型号可用于补充,并将通过纸张释放。
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无监督学习的最有前途的方法之一是将深层表示学习和深入的聚类结合在一起。最近的一些作品建议使用深层神经网络同时学习表示形式,并通过在嵌入式特征之上定义聚类损失来执行聚类。但是,这些方法对数据不平衡和分布样本敏感。结果,这些方法通过将数据推向接近随机初始化的群集中心来优化聚类。当实例的数量在不同的类别中有所不同,或者很少有样本的群集的机会较小的机会被分配给良好的质心时,这是有问题的。为了克服这些局限性,我们引入了一个新的无监督框架,用于联合表述学习和图像群集。我们同时训练两个深度学习模型,一个捕获数据分布的深度表示网络,以及一个学习嵌入式功能并执行聚类的深度聚类网络。具体而言,聚类网络和学习表示网络都利用了我们提出的统计池块,该统计数据池块代表均值,方差和基数,以处理分布外样本和类不平衡。我们的实验表明,使用这些表示形式,可以大大改善各种图像数据集的不平衡图像聚类的结果。此外,当传输到分布数据集时,学到的表示形式可以很好地推广。
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Many real-world applications of language models (LMs), such as code autocomplete and writing assistance, involve human-LM interaction, but the main LM benchmarks are non-interactive, where a system produces output without human intervention. To evaluate human-LM interaction, we develop a framework, Human-AI Language-based Interaction Evaluation (H-LINE), that expands non-interactive evaluation along three dimensions, capturing (i) the interactive process, not only the final output; (ii) the first-person subjective experience, not just a third-party assessment; and (iii) notions of preference beyond quality. We then design five tasks ranging from goal-oriented to open-ended to capture different forms of interaction. On four state-of-the-art LMs (three variants of OpenAI's GPT-3 and AI21's J1-Jumbo), we find that non-interactive performance does not always result in better human-LM interaction and that first-person and third-party metrics can diverge, suggesting the importance of examining the nuances of human-LM interaction.
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In the past few decades, there has been an explosion in the amount of available data produced from various sources with different topics. The availability of this enormous data necessitates us to adopt effective computational tools to explore the data. This leads to an intense growing interest in the research community to develop computational methods focused on processing this text data. A line of study focused on condensing the text so that we are able to get a higher level of understanding in a shorter time. The two important tasks to do this are keyword extraction and text summarization. In keyword extraction, we are interested in finding the key important words from a text. This makes us familiar with the general topic of a text. In text summarization, we are interested in producing a short-length text which includes important information about the document. The TextRank algorithm, an unsupervised learning method that is an extension of the PageRank (algorithm which is the base algorithm of Google search engine for searching pages and ranking them) has shown its efficacy in large-scale text mining, especially for text summarization and keyword extraction. this algorithm can automatically extract the important parts of a text (keywords or sentences) and declare them as the result. However, this algorithm neglects the semantic similarity between the different parts. In this work, we improved the results of the TextRank algorithm by incorporating the semantic similarity between parts of the text. Aside from keyword extraction and text summarization, we develop a topic clustering algorithm based on our framework which can be used individually or as a part of generating the summary to overcome coverage problems.
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Aiming at highly accurate object detection for connected and automated vehicles (CAVs), this paper presents a Deep Neural Network based 3D object detection model that leverages a three-stage feature extractor by developing a novel LIDAR-Camera fusion scheme. The proposed feature extractor extracts high-level features from two input sensory modalities and recovers the important features discarded during the convolutional process. The novel fusion scheme effectively fuses features across sensory modalities and convolutional layers to find the best representative global features. The fused features are shared by a two-stage network: the region proposal network (RPN) and the detection head (DH). The RPN generates high-recall proposals, and the DH produces final detection results. The experimental results show the proposed model outperforms more recent research on the KITTI 2D and 3D detection benchmark, particularly for distant and highly occluded instances.
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