现实世界中的数据通常遵循长尾巴的分布,其中一些多数类别占据了大多数数据,而大多数少数族裔类别都包含有限数量的样本。分类模型最小化跨凝结的努力来代表和分类尾部类别。尽管已经对学习无偏分类器的学习问题进行了充分的研究,但代表不平衡数据的方法却没有探索。在本文中,我们专注于表示不平衡数据的表示。最近,受到监督的对比学习最近在平衡数据上表现出了有希望的表现。但是,通过我们的理论分析,我们发现对于长尾数据,它未能形成常规的单纯形,这是代表学习的理想几何配置。为了纠正SCL的优化行为并进一步改善了长尾视觉识别的性能,我们提出了平衡对比度学习(BCL)的新型损失。与SCL相比,我们在BCL:类平均水平方面有两个改进,可以平衡负类的梯度贡献。课堂组合,允许所有类都出现在每个迷你批次中。提出的平衡对比度学习(BCL)方法满足形成常规单纯形的条件并有助于跨透明拷贝的优化。配备了BCL,提出的两分支框架可以获得更强的特征表示,并在诸如CIFAR-10-LT,CIFAR-100-LT,Imagenet-LT和Inaturalist2018之类的长尾基准数据集上实现竞争性能。我们的代码可在\ href {https://github.com/flamiezhu/bcl} {this url}中获得。
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最近,Vision Transformer模型已成为一系列视觉任务的重要模型。但是,这些模型通常是不透明的,特征可解释性较弱。此外,目前尚无针对本质上可解释的变压器构建的方法,该方法能够解释其推理过程并提供忠实的解释。为了缩小这些关键差距,我们提出了一种新型视觉变压器,称为“可解释的视觉变压器”(Ex-Vit),这是一种本质上可解释的变压器模型,能够共同发现可鲁棒的可解释特征并执行预测。具体而言,前vit由可解释的多头注意(E-MHA)模块,属性引导的解释器(ATTE)模块和自我监督属性引导的损失组成。 E-MHA裁缝可以解释的注意力重量,能够从本地贴片中学习具有噪音稳健性的模型决策的语义解释表示。同时,提议通过不同的属性发现来编码目标对象的歧视性属性特征,该发现构成了模型预测的忠实证据。此外,为我们的前武器开发了自我监督的属性引导损失,该损失旨在通过属性可区分性机制和属性多样性机制来学习增强表示形式,以定位多样性和歧视性属性并产生更健壮的解释。结果,我们可以通过拟议的前武器发现具有多种属性的忠实和强大的解释。
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The computational complexity of the self-attention mechanism in Transformer models significantly limits their ability to generalize over long temporal durations. Memory-augmentation, or the explicit storing of past information in external memory for subsequent predictions, has become a constructive avenue for mitigating this limitation. We argue that memory-augmented Transformers can benefit substantially from considering insights from the memory literature in humans. We detail an approach for integrating evidence from the human memory system through the specification of cross-domain linking hypotheses. We then provide an empirical demonstration to evaluate the use of surprisal as a linking hypothesis, and further identify the limitations of this approach to inform future research.
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我们介绍了Sparrow,这是一个寻求信息的对话代理,与提示的语言模型基线相比,训练有素,更有帮助,正确和无害。我们使用从人类反馈中的强化学习来培训我们的模型,以帮助人类评估者判断代理人的行为。首先,为了使我们的代理人更有帮助和无害,我们将良好对话的要求分解为代理人应遵循的自然语言规则,并分别向评估者询问每个规则。我们证明,这种崩溃使我们能够收集对代理行为的更多针对性的人类判断,并允许更有效的规则条件奖励模型。其次,我们的代理商在收集对模型声明的偏好判决时提供了支持事实主张的来源的证据。对于事实问题,麻雀提供的证据支持了78%的时间。比基线比基线更享受麻雀,同时对人类的对抗性探测更具弹性,在探测时只有8%的时间违反了我们的规则。最后,我们进行了广泛的分析,表明尽管我们的模型学会遵守我们的规则,但它可以表现出分布偏见。
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脑电图(EEG)信号的分类在广泛的应用中很有用,例如癫痫发作检测/预测,运动图像分类,情绪分类和药物效应诊断等。随着大量的脑电图通道获取,开发有效的数据还原方法至关重要,从一个应用程序到另一种应用程序的重要性各不相同。同样重要的是,对于许多应用程序,在脑电图录制期间实现在线分类,以监视发生的变化。在本文中,我们介绍了一种基于共同信息(MI)的方法,以进行渠道选择。获得的结果表明,尽管分类精度得分受到惩罚,但使用MI技术可以实现有希望的加速增长。将MI与含有信号转变的信号时期(3秒)一起增强了这些加速增长。这项工作是探索性的,我们建议进行进一步的研究进行验证和开发。提高分类速度的好处包括改善在临床或教育环境中的应用。
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Deep learning models can achieve high accuracy when trained on large amounts of labeled data. However, real-world scenarios often involve several challenges: Training data may become available in installments, may originate from multiple different domains, and may not contain labels for training. Certain settings, for instance medical applications, often involve further restrictions that prohibit retention of previously seen data due to privacy regulations. In this work, to address such challenges, we study unsupervised segmentation in continual learning scenarios that involve domain shift. To that end, we introduce GarDA (Generative Appearance Replay for continual Domain Adaptation), a generative-replay based approach that can adapt a segmentation model sequentially to new domains with unlabeled data. In contrast to single-step unsupervised domain adaptation (UDA), continual adaptation to a sequence of domains enables leveraging and consolidation of information from multiple domains. Unlike previous approaches in incremental UDA, our method does not require access to previously seen data, making it applicable in many practical scenarios. We evaluate GarDA on two datasets with different organs and modalities, where it substantially outperforms existing techniques.
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The development of social media user stance detection and bot detection methods rely heavily on large-scale and high-quality benchmarks. However, in addition to low annotation quality, existing benchmarks generally have incomplete user relationships, suppressing graph-based account detection research. To address these issues, we propose a Multi-Relational Graph-Based Twitter Account Detection Benchmark (MGTAB), the first standardized graph-based benchmark for account detection. To our knowledge, MGTAB was built based on the largest original data in the field, with over 1.55 million users and 130 million tweets. MGTAB contains 10,199 expert-annotated users and 7 types of relationships, ensuring high-quality annotation and diversified relations. In MGTAB, we extracted the 20 user property features with the greatest information gain and user tweet features as the user features. In addition, we performed a thorough evaluation of MGTAB and other public datasets. Our experiments found that graph-based approaches are generally more effective than feature-based approaches and perform better when introducing multiple relations. By analyzing experiment results, we identify effective approaches for account detection and provide potential future research directions in this field. Our benchmark and standardized evaluation procedures are freely available at: https://github.com/GraphDetec/MGTAB.
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As one of the prevalent methods to achieve automation systems, Imitation Learning (IL) presents a promising performance in a wide range of domains. However, despite the considerable improvement in policy performance, the corresponding research on the explainability of IL models is still limited. Inspired by the recent approaches in explainable artificial intelligence methods, we proposed a model-agnostic explaining framework for IL models called R2RISE. R2RISE aims to explain the overall policy performance with respect to the frames in demonstrations. It iteratively retrains the black-box IL model from the randomized masked demonstrations and uses the conventional evaluation outcome environment returns as the coefficient to build an importance map. We also conducted experiments to investigate three major questions concerning frames' importance equality, the effectiveness of the importance map, and connections between importance maps from different IL models. The result shows that R2RISE successfully distinguishes important frames from the demonstrations.
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Compressed videos often exhibit visually annoying artifacts, known as Perceivable Encoding Artifacts (PEAs), which dramatically degrade video visual quality. Subjective and objective measures capable of identifying and quantifying various types of PEAs are critical in improving visual quality. In this paper, we investigate the influence of four spatial PEAs (i.e. blurring, blocking, bleeding, and ringing) and two temporal PEAs (i.e. flickering and floating) on video quality. For spatial artifacts, we propose a visual saliency model with a low computational cost and higher consistency with human visual perception. In terms of temporal artifacts, self-attention based TimeSFormer is improved to detect temporal artifacts. Based on the six types of PEAs, a quality metric called Saliency-Aware Spatio-Temporal Artifacts Measurement (SSTAM) is proposed. Experimental results demonstrate that the proposed method outperforms state-of-the-art metrics. We believe that SSTAM will be beneficial for optimizing video coding techniques.
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We propose a distributionally robust return-risk model for Markov decision processes (MDPs) under risk and reward ambiguity. The proposed model optimizes the weighted average of mean and percentile performances, and it covers the distributionally robust MDPs and the distributionally robust chance-constrained MDPs (both under reward ambiguity) as special cases. By considering that the unknown reward distribution lies in a Wasserstein ambiguity set, we derive the tractable reformulation for our model. In particular, we show that that the return-risk model can also account for risk from uncertain transition kernel when one only seeks deterministic policies, and that a distributionally robust MDP under the percentile criterion can be reformulated as its nominal counterpart at an adjusted risk level. A scalable first-order algorithm is designed to solve large-scale problems, and we demonstrate the advantages of our proposed model and algorithm through numerical experiments.
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