由于毫米波通信中使用的非常狭窄的光束(MMWave),光束对准(BA)是一个关键问题。在这项工作中,我们研究了MMWave BA的问题,并根据机器学习策略贝叶斯优化(BO)提出了一种新颖的光束对齐方案。在这种情况下,我们将光束对齐问题视为黑匣子功能,然后使用BO找到可能的最佳光束对。在BA过程中,该策略利用了测量光束对的信息来预测最佳的光束对。此外,我们建议一种基于梯度增强回归树模型的新型BO算法。仿真结果证明了使用三种不同的替代模型,我们提出的BA方案的光谱效率性能。他们还表明,与正交匹配追踪(OMP)算法和基于汤普森采样的多臂Bandit(TS-MAB)方法相比,所提出的方案可以用小型开销实现光谱效率。
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社交机器人被称为社交网络上的自动帐户,这些帐户试图像人类一样行事。尽管图形神经网络(GNNS)已大量应用于社会机器人检测领域,但大量的领域专业知识和先验知识大量参与了最先进的方法,以设计专门的神经网络体系结构,以设计特定的神经网络体系结构。分类任务。但是,在模型设计中涉及超大的节点和网络层,通常会导致过度平滑的问题和缺乏嵌入歧视。在本文中,我们提出了罗斯加斯(Rosgas),这是一种新颖的加强和自我监督的GNN Architecture搜索框架,以适应性地指出了最合适的多跳跃社区和GNN体系结构中的层数。更具体地说,我们将社交机器人检测问题视为以用户为中心的子图嵌入和分类任务。我们利用异构信息网络来通过利用帐户元数据,关系,行为特征和内容功能来展示用户连接。 Rosgas使用多代理的深钢筋学习(RL)机制来导航最佳邻域和网络层的搜索,以分别学习每个目标用户的子图嵌入。开发了一种用于加速RL训练过程的最接近的邻居机制,Rosgas可以借助自我监督的学习来学习更多的判别子图。 5个Twitter数据集的实验表明,Rosgas在准确性,训练效率和稳定性方面优于最先进的方法,并且在处理看不见的样本时具有更好的概括。
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神经辐射场(NERFS)表现出惊人的能力,可以从新颖的观点中综合3D场景的图像。但是,他们依赖于基于射线行进的专门体积渲染算法,这些算法与广泛部署的图形硬件的功能不匹配。本文介绍了基于纹理多边形的新的NERF表示形式,该表示可以有效地与标准渲染管道合成新型图像。 NERF表示为一组多边形,其纹理代表二进制不相处和特征向量。用Z-Buffer对多边形的传统渲染产生了每个像素的图像,该图像由在片段着色器中运行的小型,观点依赖的MLP来解释,以产生最终的像素颜色。这种方法使NERF可以使用传统的Polygon栅格化管道渲染,该管道提供了庞大的像素级并行性,从而在包括移动电话在内的各种计算平台上实现了交互式帧速率。
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作为药物开发的必要过程,找到可以选择性地与特定蛋白质结合的药物化合物是高度挑战性和昂贵的。代表药物目标相互作用(DTI)强度的药物目标亲和力(DTA)在过去十年中在DTI预测任务中发挥了重要作用。尽管已将深度学习应用于与DTA相关的研究,但现有的解决方案忽略了分子亚结构之间的基本相关性,在分子代表学习药物化合物分子/蛋白质靶标之间。此外,传统方法缺乏DTA预测过程的解释性。这导致缺少分子间相互作用的特征信息,从而影响预测性能。因此,本文提出了一种使用交互式学习和自动编码器机制的DTA预测方法。提出的模型增强了通过药物/蛋白质分子表示学习模块捕获单个分子序列的特征信息的相应能力,并通过交互式信息学习模块补充了分子序列对之间的信息相互作用。 DTA值预测模块融合了药物目标对相互作用信息,以输出DTA的预测值。此外,从理论上讲,本文提出的方法最大化了DTA预测模型联合分布的证据下限(ELBO),从而增强了实际值和预测值之间概率分布的一致性。实验结果证实了相互变压器 - 药物目标亲和力(MT-DTA)的性能比其他比较方法更好。
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We advocate the use of implicit fields for learning generative models of shapes and introduce an implicit field decoder, called IM-NET, for shape generation, aimed at improving the visual quality of the generated shapes. An implicit field assigns a value to each point in 3D space, so that a shape can be extracted as an iso-surface. IM-NET is trained to perform this assignment by means of a binary classifier. Specifically, it takes a point coordinate, along with a feature vector encoding a shape, and outputs a value which indicates whether the point is outside the shape or not. By replacing conventional decoders by our implicit decoder for representation learning (via IM-AE) and shape generation (via IM-GAN), we demonstrate superior results for tasks such as generative shape modeling, interpolation, and single-view 3D reconstruction, particularly in terms of visual quality. Code and supplementary material are available at https://github.com/czq142857/implicit-decoder.
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Dataset distillation has emerged as a prominent technique to improve data efficiency when training machine learning models. It encapsulates the knowledge from a large dataset into a smaller synthetic dataset. A model trained on this smaller distilled dataset can attain comparable performance to a model trained on the original training dataset. However, the existing dataset distillation techniques mainly aim at achieving the best trade-off between resource usage efficiency and model utility. The security risks stemming from them have not been explored. This study performs the first backdoor attack against the models trained on the data distilled by dataset distillation models in the image domain. Concretely, we inject triggers into the synthetic data during the distillation procedure rather than during the model training stage, where all previous attacks are performed. We propose two types of backdoor attacks, namely NAIVEATTACK and DOORPING. NAIVEATTACK simply adds triggers to the raw data at the initial distillation phase, while DOORPING iteratively updates the triggers during the entire distillation procedure. We conduct extensive evaluations on multiple datasets, architectures, and dataset distillation techniques. Empirical evaluation shows that NAIVEATTACK achieves decent attack success rate (ASR) scores in some cases, while DOORPING reaches higher ASR scores (close to 1.0) in all cases. Furthermore, we conduct a comprehensive ablation study to analyze the factors that may affect the attack performance. Finally, we evaluate multiple defense mechanisms against our backdoor attacks and show that our attacks can practically circumvent these defense mechanisms.
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Blind image quality assessment (BIQA) remains challenging due to the diversity of distortion and image content variation, which complicate the distortion patterns crossing different scales and aggravate the difficulty of the regression problem for BIQA. However, existing BIQA methods often fail to consider multi-scale distortion patterns and image content, and little research has been done on learning strategies to make the regression model produce better performance. In this paper, we propose a simple yet effective Progressive Multi-Task Image Quality Assessment (PMT-IQA) model, which contains a multi-scale feature extraction module (MS) and a progressive multi-task learning module (PMT), to help the model learn complex distortion patterns and better optimize the regression issue to align with the law of human learning process from easy to hard. To verify the effectiveness of the proposed PMT-IQA model, we conduct experiments on four widely used public datasets, and the experimental results indicate that the performance of PMT-IQA is superior to the comparison approaches, and both MS and PMT modules improve the model's performance.
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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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Given the increasingly intricate forms of partial differential equations (PDEs) in physics and related fields, computationally solving PDEs without analytic solutions inevitably suffers from the trade-off between accuracy and efficiency. Recent advances in neural operators, a kind of mesh-independent neural-network-based PDE solvers, have suggested the dawn of overcoming this challenge. In this emerging direction, Koopman neural operator (KNO) is a representative demonstration and outperforms other state-of-the-art alternatives in terms of accuracy and efficiency. Here we present KoopmanLab, a self-contained and user-friendly PyTorch module of the Koopman neural operator family for solving partial differential equations. Beyond the original version of KNO, we develop multiple new variants of KNO based on different neural network architectures to improve the general applicability of our module. These variants are validated by mesh-independent and long-term prediction experiments implemented on representative PDEs (e.g., the Navier-Stokes equation and the Bateman-Burgers equation) and ERA5 (i.e., one of the largest high-resolution data sets of global-scale climate fields). These demonstrations suggest the potential of KoopmanLab to be considered in diverse applications of partial differential equations.
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A recent study has shown a phenomenon called neural collapse in that the within-class means of features and the classifier weight vectors converge to the vertices of a simplex equiangular tight frame at the terminal phase of training for classification. In this paper, we explore the corresponding structures of the last-layer feature centers and classifiers in semantic segmentation. Based on our empirical and theoretical analysis, we point out that semantic segmentation naturally brings contextual correlation and imbalanced distribution among classes, which breaks the equiangular and maximally separated structure of neural collapse for both feature centers and classifiers. However, such a symmetric structure is beneficial to discrimination for the minor classes. To preserve these advantages, we introduce a regularizer on feature centers to encourage the network to learn features closer to the appealing structure in imbalanced semantic segmentation. Experimental results show that our method can bring significant improvements on both 2D and 3D semantic segmentation benchmarks. Moreover, our method ranks 1st and sets a new record (+6.8% mIoU) on the ScanNet200 test leaderboard. Code will be available at https://github.com/dvlab-research/Imbalanced-Learning.
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