大脑提取是预处理3D脑MRI数据的第一步之一。它是任何即将进行的大脑成像分析的先决条件。但是,由于大脑和人头的复杂结构,这并不是一个简单的分割问题。尽管文献中已经提出了多种解决方案,但我们仍然没有真正强大的方法。尽管以前的方法已将机器学习与结构/几何先验使用,但随着计算机视觉任务中深度学习的发展,对于此语义分割任务,建议的卷积神经网络体系结构有所增加。但是,大多数模型都致力于改善培训数据和损失功能,而架构的变化很小。在本文中,我们提出了一种称为EVC-NET的新颖架构。 EVC-NET在每个编码器块上添加了较低的比例输入。这增强了V-NET体系结构的多尺度方案,从而提高了模型的效率。有条件的随机字段,是深度学习时代之前的图像分割的一种流行方法,在这里重新引入,作为完善网络输出以捕获细分粒度结果的额外步骤。我们将我们的模型与HD-BET,Synthstrip和Brainy等最新方法进行比较。结果表明,即使训练资源有限,EVC-NET也可以达到更高的骰子系数和Jaccard指数以及较低的表面距离。
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This paper proposes a new regularization algorithm referred to as macro-block dropout. The overfitting issue has been a difficult problem in training large neural network models. The dropout technique has proven to be simple yet very effective for regularization by preventing complex co-adaptations during training. In our work, we define a macro-block that contains a large number of units from the input to a Recurrent Neural Network (RNN). Rather than applying dropout to each unit, we apply random dropout to each macro-block. This algorithm has the effect of applying different drop out rates for each layer even if we keep a constant average dropout rate, which has better regularization effects. In our experiments using Recurrent Neural Network-Transducer (RNN-T), this algorithm shows relatively 4.30 % and 6.13 % Word Error Rates (WERs) improvement over the conventional dropout on LibriSpeech test-clean and test-other. With an Attention-based Encoder-Decoder (AED) model, this algorithm shows relatively 4.36 % and 5.85 % WERs improvement over the conventional dropout on the same test sets.
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Neural fields, also known as coordinate-based or implicit neural representations, have shown a remarkable capability of representing, generating, and manipulating various forms of signals. For video representations, however, mapping pixel-wise coordinates to RGB colors has shown relatively low compression performance and slow convergence and inference speed. Frame-wise video representation, which maps a temporal coordinate to its entire frame, has recently emerged as an alternative method to represent videos, improving compression rates and encoding speed. While promising, it has still failed to reach the performance of state-of-the-art video compression algorithms. In this work, we propose FFNeRV, a novel method for incorporating flow information into frame-wise representations to exploit the temporal redundancy across the frames in videos inspired by the standard video codecs. Furthermore, we introduce a fully convolutional architecture, enabled by one-dimensional temporal grids, improving the continuity of spatial features. Experimental results show that FFNeRV yields the best performance for video compression and frame interpolation among the methods using frame-wise representations or neural fields. To reduce the model size even further, we devise a more compact convolutional architecture using the group and pointwise convolutions. With model compression techniques, including quantization-aware training and entropy coding, FFNeRV outperforms widely-used standard video codecs (H.264 and HEVC) and performs on par with state-of-the-art video compression algorithms.
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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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Neural radiance fields (NeRF) have demonstrated the potential of coordinate-based neural representation (neural fields or implicit neural representation) in neural rendering. However, using a multi-layer perceptron (MLP) to represent a 3D scene or object requires enormous computational resources and time. There have been recent studies on how to reduce these computational inefficiencies by using additional data structures, such as grids or trees. Despite the promising performance, the explicit data structure necessitates a substantial amount of memory. In this work, we present a method to reduce the size without compromising the advantages of having additional data structures. In detail, we propose using the wavelet transform on grid-based neural fields. Grid-based neural fields are for fast convergence, and the wavelet transform, whose efficiency has been demonstrated in high-performance standard codecs, is to improve the parameter efficiency of grids. Furthermore, in order to achieve a higher sparsity of grid coefficients while maintaining reconstruction quality, we present a novel trainable masking approach. Experimental results demonstrate that non-spatial grid coefficients, such as wavelet coefficients, are capable of attaining a higher level of sparsity than spatial grid coefficients, resulting in a more compact representation. With our proposed mask and compression pipeline, we achieved state-of-the-art performance within a memory budget of 2 MB. Our code is available at https://github.com/daniel03c1/masked_wavelet_nerf.
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Constrained reinforcement learning (RL) is an area of RL whose objective is to find an optimal policy that maximizes expected cumulative return while satisfying a given constraint. Most of the previous constrained RL works consider expected cumulative sum cost as the constraint. However, optimization with this constraint cannot guarantee a target probability of outage event that the cumulative sum cost exceeds a given threshold. This paper proposes a framework, named Quantile Constrained RL (QCRL), to constrain the quantile of the distribution of the cumulative sum cost that is a necessary and sufficient condition to satisfy the outage constraint. This is the first work that tackles the issue of applying the policy gradient theorem to the quantile and provides theoretical results for approximating the gradient of the quantile. Based on the derived theoretical results and the technique of the Lagrange multiplier, we construct a constrained RL algorithm named Quantile Constrained Policy Optimization (QCPO). We use distributional RL with the Large Deviation Principle (LDP) to estimate quantiles and tail probability of the cumulative sum cost for the implementation of QCPO. The implemented algorithm satisfies the outage probability constraint after the training period.
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The recent advent of play-to-earn (P2E) systems in massively multiplayer online role-playing games (MMORPGs) has made in-game goods interchangeable with real-world values more than ever before. The goods in the P2E MMORPGs can be directly exchanged with cryptocurrencies such as Bitcoin, Ethereum, or Klaytn via blockchain networks. Unlike traditional in-game goods, once they had been written to the blockchains, P2E goods cannot be restored by the game operation teams even with chargeback fraud such as payment fraud, cancellation, or refund. To tackle the problem, we propose a novel chargeback fraud prediction method, PU GNN, which leverages graph attention networks with PU loss to capture both the players' in-game behavior with P2E token transaction patterns. With the adoption of modified GraphSMOTE, the proposed model handles the imbalanced distribution of labels in chargeback fraud datasets. The conducted experiments on two real-world P2E MMORPG datasets demonstrate that PU GNN achieves superior performances over previously suggested methods.
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最近的深度学习模型在言语增强方面已经达到了高性能。但是,获得快速和低复杂模型而没有明显的性能降解仍然是一项挑战。以前的知识蒸馏研究对言语增强无法解决这个问题,因为它们的输出蒸馏方法在某些方面不符合语音增强任务。在这项研究中,我们提出了基于特征的蒸馏多视图注意转移(MV-AT),以在时域中获得有效的语音增强模型。基于多视图功能提取模型,MV-AT将教师网络的多视图知识传输到学生网络,而无需其他参数。实验结果表明,所提出的方法始终提高瓦伦蒂尼和深噪声抑制(DNS)数据集的各种规模的学生模型的性能。与基线模型相比,使用我们提出的方法(一种用于有效部署的轻巧模型)分别使用了15.4倍和4.71倍(FLOPS),与具有相似性能的基线模型相比,Many-S-8.1GF分别达到了15.4倍和4.71倍。
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手语制作(SLP)旨在将语言的表达方式转化为手语的相应语言,例如基于骨架的标志姿势或视频。现有的SLP型号是自动回旋(AR)或非自动入口(NAR)。但是,AR-SLP模型在解码过程中遭受了回归对均值和误差传播的影响。 NSLP-G是一种基于NAR的模型,在某种程度上解决了这些问题,但会带来其他问题。例如,它不考虑目标符号长度,并且会遭受虚假解码启动的影响。我们通过知识蒸馏(KD)提出了一种新型的NAR-SLP模型,以解决这些问题。首先,我们设计一个长度调节器来预测生成的符号姿势序列的末端。然后,我们采用KD,该KD从预训练的姿势编码器中提取空间语言特征以减轻虚假解码的启动。广泛的实验表明,所提出的方法在特里切特的手势距离和背面翻译评估中都显着优于现有的SLP模型。
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视觉预训练的最新进展表明,在不同的视觉任务中表现出惊人的表现,阐明了对人工智能研究中对视觉和文本概念的全面理解的长期问题。但是,在医学领域的视觉预训练的应用方面取得了有限数量和多样性阻碍了对联合视觉语言概念的成功学习。在这项研究中,我们介绍了Max-VL,这是一种针对医疗领域中有效视觉预训练的模型。我们在实验上证明,预先训练的MAX-VL模型在各种视觉任务中都优于当前最新视觉语言模型。我们还提出了用于诊断新出现疾病和人为错误检测的临床实用性,并显示了该模型在不同领域数据中的广泛适用性。
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