In this paper, we investigate the joint device activity and data detection in massive machine-type communications (mMTC) with a one-phase non-coherent scheme, where data bits are embedded in the pilot sequences and the base station simultaneously detects active devices and their embedded data bits without explicit channel estimation. Due to the correlated sparsity pattern introduced by the non-coherent transmission scheme, the traditional approximate message passing (AMP) algorithm cannot achieve satisfactory performance. Therefore, we propose a deep learning (DL) modified AMP network (DL-mAMPnet) that enhances the detection performance by effectively exploiting the pilot activity correlation. The DL-mAMPnet is constructed by unfolding the AMP algorithm into a feedforward neural network, which combines the principled mathematical model of the AMP algorithm with the powerful learning capability, thereby benefiting from the advantages of both techniques. Trainable parameters are introduced in the DL-mAMPnet to approximate the correlated sparsity pattern and the large-scale fading coefficient. Moreover, a refinement module is designed to further advance the performance by utilizing the spatial feature caused by the correlated sparsity pattern. Simulation results demonstrate that the proposed DL-mAMPnet can significantly outperform traditional algorithms in terms of the symbol error rate performance.
translated by 谷歌翻译
基于深度学习的NLP模型被发现容易受到Word替代扰动的影响。在他们被广泛采用之前,需要解决坚固性的基本问题。沿着这条线,我们提出了一个正式的框架来评估词语级鲁棒性。首先,要研究模型的安全区域,我们引入了稳健的半径,这是模型可以抵抗任何扰动的边界。计算最大鲁棒性半径的计算变硬,我们估计其上限和下限。我们将攻击方法作为寻求上限和设计伪动态编程算法的攻击方法,用于更紧密的上限。然后验证方法用于下限。此外,为了评估在安全半径之外的区域的稳健性,我们从另一个视图中重新征服鲁棒性:量化。引入了具有严格统计保障的鲁棒度量,以测量对抗性示例的定量,这表明该模型对安全半径之外的扰动的敏感性。该度量有助于我们弄清楚为什么伯特这样的最先进的模型可以很容易地被几个单词替换所吸引,但在现实世界的噪音存在下概括很好。
translated by 谷歌翻译
随着深度学习技术的快速发展,各种最近的工作试图应用图形神经网络(GNN)来解决诸如布尔满足(SAT)之类的NP硬问题,这表明了桥接机器学习与象征性差距的潜力。然而,GNN预测的解决方案的质量并未在文献中进行很好地研究。在本文中,我们研究了GNNS在学习中解决最大可满足性(MaxSAT)问题的能力,从理论和实践角度来看。我们构建了两种GNN模型来学习来自基准的MaxSAT实例的解决方案,并显示GNN通过实验评估解决MaxSAT问题的有吸引力。我们还基于算法对准理论,我们还提出了GNNS可以在一定程度上学会解决MaxSAT问题的影响的理论解释。
translated by 谷歌翻译
Weakly-supervised object localization aims to indicate the category as well as the scope of an object in an image given only the image-level labels. Most of the existing works are based on Class Activation Mapping (CAM) and endeavor to enlarge the discriminative area inside the activation map to perceive the whole object, yet ignore the co-occurrence confounder of the object and context (e.g., fish and water), which makes the model inspection hard to distinguish object boundaries. Besides, the use of CAM also brings a dilemma problem that the classification and localization always suffer from a performance gap and can not reach their highest accuracy simultaneously. In this paper, we propose a casual knowledge distillation method, dubbed KD-CI-CAM, to address these two under-explored issues in one go. More specifically, we tackle the co-occurrence context confounder problem via causal intervention (CI), which explores the causalities among image features, contexts, and categories to eliminate the biased object-context entanglement in the class activation maps. Based on the de-biased object feature, we additionally propose a multi-teacher causal distillation framework to balance the absorption of classification knowledge and localization knowledge during model training. Extensive experiments on several benchmarks demonstrate the effectiveness of KD-CI-CAM in learning clear object boundaries from confounding contexts and addressing the dilemma problem between classification and localization performance.
translated by 谷歌翻译
Recently, the success of pre-training in text domain has been fully extended to vision, audio, and cross-modal scenarios. The proposed pre-training models of different modalities are showing a rising trend of homogeneity in their model structures, which brings the opportunity to implement different pre-training models within a uniform framework. In this paper, we present TencentPretrain, a toolkit supporting pre-training models of different modalities. The core feature of TencentPretrain is the modular design. The toolkit uniformly divides pre-training models into 5 components: embedding, encoder, target embedding, decoder, and target. As almost all of common modules are provided in each component, users can choose the desired modules from different components to build a complete pre-training model. The modular design enables users to efficiently reproduce existing pre-training models or build brand-new one. We test the toolkit on text, vision, and audio benchmarks and show that it can match the performance of the original implementations.
translated by 谷歌翻译
A common scenario of Multilingual Neural Machine Translation (MNMT) is that each translation task arrives in a sequential manner, and the training data of previous tasks is unavailable. In this scenario, the current methods suffer heavily from catastrophic forgetting (CF). To alleviate the CF, we investigate knowledge distillation based life-long learning methods. Specifically, in one-tomany scenario, we propose a multilingual distillation method to make the new model (student) jointly learn multilingual output from old model (teacher) and new task. In many-to one scenario, we find that direct distillation faces the extreme partial distillation problem, and we propose two different methods to address it: pseudo input distillation and reverse teacher distillation. The experimental results on twelve translation tasks show that the proposed methods can better consolidate the previous knowledge and sharply alleviate the CF.
translated by 谷歌翻译
With the deterioration of climate, the phenomenon of rain-induced flooding has become frequent. To mitigate its impact, recent works adopt convolutional neural networks or other variants to predict the floods. However, these methods directly force the model to reconstruct the raw pixels of water depth maps through constraining pixel-level differences, ignoring the high-level information contained in terrain features and rainfall patterns. To address this, we present a novel GAN-based framework for precise flood prediction, which incorporates hierarchical terrain spatial attention to help the model focus on spatially-salient areas of terrain features and constructs multi-scale rainfall embedding to extensively integrate rainfall pattern information into generation. To better adapt the model in various rainfall conditions, we leverage a rainfall regression loss for both the generator and the discriminator as additional supervision. Extensive evaluations on real catchment datasets demonstrate the superior performance of our method, which greatly surpasses the previous arts under different rainfall conditions.
translated by 谷歌翻译
Deep learning methods have contributed substantially to the rapid advancement of medical image segmentation, the quality of which relies on the suitable design of loss functions. Popular loss functions, including the cross-entropy and dice losses, often fall short of boundary detection, thereby limiting high-resolution downstream applications such as automated diagnoses and procedures. We developed a novel loss function that is tailored to reflect the boundary information to enhance the boundary detection. As the contrast between segmentation and background regions along the classification boundary naturally induces heterogeneity over the pixels, we propose the piece-wise two-sample t-test augmented (PTA) loss that is infused with the statistical test for such heterogeneity. We demonstrate the improved boundary detection power of the PTA loss compared to benchmark losses without a t-test component.
translated by 谷歌翻译
大脑计算机界面(BCI)提供了人脑和外部设备之间的直接通信途径。在新受试者可以使用BCI之前,通常需要进行校准程序。因为间和受试者内部的差异是如此之大,以至于由现有受试者训练的模型在新受试者方面的表现不佳。因此,有效的主题转移和校准方法至关重要。在本文中,我们提出了一种半监督的元学习(SSML)方法,用于BCIS的主题转移学习。拟议的SSML首先学习了具有现有受试者的元模型,然后以半监督的学习方式对模型进行微调,即使用很少的标记和许多未标记的目标对象样本进行校准。对于标记数据稀缺或昂贵的同时,无标记数据的BCI应用程序非常重要。为了验证SSML方法,测试了三种不同的BCI范例:1)与事件相关的潜在检测; 2)情绪识别; 3)睡眠舞台。 SSML在前两个范式上取得了显着提高15%,而第三个范式则达到4.9%。实验结果证明了SSML方法在BCI应用中的有效性和潜力。
translated by 谷歌翻译
语义通信引起了人们的兴趣,因为它可以显着减少在不丢失关键信息的情况下要传输的数据量。大多数现有作品都探索文本的语义编码和传输,并在自然语言处理(NLP)中应用技术来解释文本的含义。在本文中,我们构想了图像数据的语义通信,这些语义数据在语义和带宽敏感方面更为丰富。我们提出了一种基于增强学习的自适应语义编码(RL-ASC)方法,该方法编码超过像素级别的图像。首先,我们定义了图像数据的语义概念,该概念包括类别,空间布置和视觉特征作为表示单元,并提出卷积语义编码器以提取语义概念。其次,我们提出了图像重建标准,该标准从传统像素的相似性演变为语义相似性和感知性能。第三,我们设计了一种基于RL的新型语义位分配模型,其奖励是用自适应量化水平编码某个语义概念后的速率语义感知性能的提高。因此,与任务相关的信息得到正确保存和重建,同时丢弃了较少重要的数据。最后,我们提出了基于生成的对抗网(GAN)的语义解码器,该语义解码器通过注意模块融合本地和全球特征。实验结果表明,所提出的RL-ASC具有噪声稳定性,可以重建视觉上令人愉悦和语义一致的图像,并节省与标准编解码器和其他基于深度学习的图像编解码器相比,可以节省位置的时间。
translated by 谷歌翻译