Stochastic human motion prediction aims to forecast multiple plausible future motions given a single pose sequence from the past. Most previous works focus on designing elaborate losses to improve the accuracy, while the diversity is typically characterized by randomly sampling a set of latent variables from the latent prior, which is then decoded into possible motions. This joint training of sampling and decoding, however, suffers from posterior collapse as the learned latent variables tend to be ignored by a strong decoder, leading to limited diversity. Alternatively, inspired by the diffusion process in nonequilibrium thermodynamics, we propose MotionDiff, a diffusion probabilistic model to treat the kinematics of human joints as heated particles, which will diffuse from original states to a noise distribution. This process offers a natural way to obtain the "whitened" latents without any trainable parameters, and human motion prediction can be regarded as the reverse diffusion process that converts the noise distribution into realistic future motions conditioned on the observed sequence. Specifically, MotionDiff consists of two parts: a spatial-temporal transformer-based diffusion network to generate diverse yet plausible motions, and a graph convolutional network to further refine the outputs. Experimental results on two datasets demonstrate that our model yields the competitive performance in terms of both accuracy and diversity.
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先前关于人类运动预测的工作遵循观察到的序列与要预测的序列之间建立映射关系的模式。但是,由于多元时间序列数据的固有复杂性,找到运动序列之间的外推关系仍然是一个挑战。在本文中,我们提出了一种新的预测模式,该模式介绍了以前被忽视的人类姿势,以从插值的角度实施预测任务。这些姿势在预测序列后存在,并形成特权序列。要具体而言,我们首先提出了一个插值学习网络(ITP-NETWORK),该网络既编码观察到的序列和特权序列,以插入预测的序列之间,其中嵌入式的特权序列 - 编码器(Priv-incoder)学习了这些序列特权知识(PK)同时。然后,我们提出了一个最终的预测网络(FP-NETWORK),该网络无法观察到特权序列,但配备了一种新型的PK模拟器,该序列可以提取从先前的网络中学到的PK。该模拟器作为输入观察到的序列,但近似私有编码器的行为,从而使fp-network模仿插值过程。广泛的实验结果表明,在短期和长期预测中,我们的预测模式在基准的H.36M,CMU-MOCAP和3DPW数据集上实现了最先进的性能。
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在许多真实的场景中,我们经常处理随着时间的推移顺序收集的流数据。由于环境的非静止性,流数据分布可能以不可预测的方式改变,这被称为概念漂移。为了处理概念漂移,先前的方法首先检测概念漂移的时间何时/其中,然后适应模型以适应最新数据的分布。然而,仍然存在许多情况下,环境进化的一些潜在因素是可预测的,使得可以模拟流数据的未来概念漂移趋势,而在以前的工作中没有完全探索这种情况。在本文中,我们提出了一种新型方法DDG-DA,可以有效地预测数据分布的演变并提高模型的性能。具体而言,我们首先训练预测器来估计未来的数据分布,然后利用它来生成训练样本,最后在生成的数据上培训模型。我们对三个现实世界任务进行实验(预测股票价格走势,电力负荷和太阳辐照度),并获得多种广泛使用的模型的显着改进。
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优化平均精度(AP)的近似已被广泛研究图像检索。受AP的定义有限,这些方法考虑在每个阳性实例之前的负数和正面情况。但是,我们声称只在积极的情况下惩罚负面情况,因为损失只来自这些负面情况。为此,我们提出了一种新的损失,即惩罚正面(PNP)的负面情况,这可以直接最小化每个正面前的负实例的数量。此外,基于AP的方法采用固定和次优梯度分配策略。因此,我们通过构建损耗的衍生功能来系统地调查不同的梯度分配解决方案,导致PNP-I具有增加的衍生函数和PNP-D,其具有减小的函数。 PNP-I通过为它们分配更大的渐变并尝试使所有相关实例更近的较大渐变来重点缩影。相比之下,PNP-D对此类实例的关注不那么注意,并慢慢纠正它们。对于大多数真实世界的数据,一类通常包含几个本地群集。 PNP-我盲目地聚集了这些群集,而PNP-D保持它们。因此,PNP-D更优越。三个标准检索数据集的实验显示了上述分析的一致结果。广泛的评估表明PNP-D实现了最先进的性能。代码在https://github.com/interestingzhuo/pnp_loss获得
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Knowledge tracing (KT) aims to leverage students' learning histories to estimate their mastery levels on a set of pre-defined skills, based on which the corresponding future performance can be accurately predicted. In practice, a student's learning history comprises answers to sets of massed questions, each known as a session, rather than merely being a sequence of independent answers. Theoretically, within and across these sessions, students' learning dynamics can be very different. Therefore, how to effectively model the dynamics of students' knowledge states within and across the sessions is crucial for handling the KT problem. Most existing KT models treat student's learning records as a single continuing sequence, without capturing the sessional shift of students' knowledge state. To address the above issue, we propose a novel hierarchical transformer model, named HiTSKT, comprises an interaction(-level) encoder to capture the knowledge a student acquires within a session, and a session(-level) encoder to summarise acquired knowledge across the past sessions. To predict an interaction in the current session, a knowledge retriever integrates the summarised past-session knowledge with the previous interactions' information into proper knowledge representations. These representations are then used to compute the student's current knowledge state. Additionally, to model the student's long-term forgetting behaviour across the sessions, a power-law-decay attention mechanism is designed and deployed in the session encoder, allowing it to emphasize more on the recent sessions. Extensive experiments on three public datasets demonstrate that HiTSKT achieves new state-of-the-art performance on all the datasets compared with six state-of-the-art KT models.
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Deep Learning has significantly impacted the application of data-to-decision throughout research and industry, however, they lack a rigorous mathematical foundation, which creates situations where algorithmic results fail to be practically invertible. In this paper we present a nearly invertible mapping between $\mathbb{R}^{2^n}$ and $\mathbb{R}^{n+1}$ via a topological connection between $S^{2^n-1}$ and $S^n$. Throughout the paper we utilize the algebra of Multicomplex rotation groups and polyspherical coordinates to define two maps: the first is a contraction from $S^{2^n-1}$ to $\displaystyle \otimes^n_{k=1} SO(2)$, and the second is a projection from $\displaystyle \otimes^n_{k=1} SO(2)$ to $S^{n}$. Together these form a composite map that we call the LG Fibration. In analogy to the generation of Hopf Fibration using Hypercomplex geometry from $S^{(2n-1)} \mapsto CP^n$, our fibration uses Multicomplex geometry to project $S^{2^n-1}$ onto $S^n$. We also investigate the algebraic properties of the LG Fibration, ultimately deriving a distance difference function to determine which pairs of vectors have an invariant inner product under the transformation. The LG Fibration has applications to Machine Learning and AI, in analogy to the current applications of Hopf Fibrations in adaptive UAV control. Furthermore, the ability to invert the LG Fibration for nearly all elements allows for the development of Machine Learning algorithms that may avoid the issues of uncertainty and reproducibility that currently plague contemporary methods. The primary result of this paper is a novel method of nearly invertible geometric dimensional reduction from $S^{2^n-1}$ to $S^n$, which has the capability to extend the research in both mathematics and AI, including but not limited to the fields of homotopy groups of spheres, algebraic topology, machine learning, and algebraic biology.
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来自数据的顺序模式是各种时间序列预测任务的核心。深度学习模型大大优于许多传统模型,但是这些黑框模型通常缺乏预测和决策的解释性。为了揭示具有可理解的数学表达式的潜在趋势,科学家和经济学家倾向于使用部分微分方程(PDE)来解释顺序模式的高度非线性动力学。但是,它通常需要领域专家知识和一系列简化的假设,这些假设并不总是实用的,并且可能偏离不断变化的世界。是否可以动态地学习与数据的差异关系以解释时间不断发展的动态?在这项工作中,我们提出了一个学习框架,该框架可以自动从顺序数据中获取可解释的PDE模型。特别是,该框架由可学习的差分块组成,称为$ p $ blocks,事实证明,该框架能够近似于理论上随着时间不断变化的复杂连续功能。此外,为了捕获动力学变化,该框架引入了元学习控制器,以动态优化混合PDE模型的超参数。 《时代》系列预测金融,工程和健康数据的广泛实验表明,我们的模型可以提供有价值的解释性并实现与最先进模型相当的性能。从经验研究中,我们发现学习一些差异操作员可能会捕获无需大量计算复杂性的顺序动力学的主要趋势。
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多模式知识图(MKG)不仅包括关系三重态,还包括相关的多模式辅助数据(即文本和图像),从而增强了知识的多样性。然而,自然的不完整严重阻碍了MKG的应用。为了解决该问题,现有研究采用基于嵌入的推理模型来融合多模式特征后推断缺失的知识。但是,由于以下问题,这些方法的推理性能受到限制:(1)多模式辅助特征的无效融合; (2)缺乏复杂的推理能力以及无法进行多跳的推理,该推理能够推断出更多的知识。为了克服这些问题,我们提出了一个名为MMKGR(多模式知识图推理)的新型模型。具体而言,该模型包含以下两个组件:(1)统一的栅极注意网络,旨在通过充分的注意力相互作用和降低噪声来生成有效的多模式互补特征; (2)一种补充特征感知的增强学习方法,该方法根据组件(1)中获得的特征,通过执行多跳的推理过程来预测丢失元素。实验结果表明,MMKGR在MKG推理任务中的最新方法优于最先进的方法。
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归纳链路预测(ILP)是考虑到新兴知识图(kgs)中未见实体的联系,考虑到KGS的发展性质。一个更具挑战性的场景是,新兴的kg仅由看不见的实体组成,被称为已断开新兴kgs(DEKGS)。 DEKGS的现有研究仅专注于预测封闭链接,即预测新兴KG内部的联系。到目前为止,先前的工作尚未对将进化信息从原始KG到DEKG进行进化信息。为了填补空白,我们提出了一个名为DEKG-ILP的新型模型(由以下两个组成部分组成的dekg-ilp(断开新兴知识图形的归纳链路预测)。 (1)模块CLRM(基于对比的关系特定特征特征建模)是为了提取基于全球关系的语义特征而开发的,它们在原始KGS和DEKGS之间以新颖的采样策略共享。 (2)提出了模块GSM(基于GNN的子图建模),以提取围绕KGS中每个链接的局部子图拓扑信息。在几个基准数据集上进行的广泛实验表明,与最新方法相比,DEKG-ILP具有明显的性能改进,用于封闭和桥接链路预测。源代码可在线获得。
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本文介绍了机器学习推动的各种脑电图应用程序和当前的脑电图市场生态系统。使用脑电图越来越多的开放医疗和健康数据集鼓励数据驱动的研究,并有望通过知识发现和机器学习数据科学算法开发来改善患者护理的神经病学。这项工作导致各种脑电图发展,目前构成了新的脑电图市场。本文试图对脑电图市场进行全面的调查,并涵盖脑电图的六个重要应用,包括诊断/筛查,药物开发,神经营销,日常健康,元元和年龄/残疾援助。这项调查的重点是研究领域与商业市场之间的比较和对比。我们的调查指出了脑电图的当前局限性,并指示了上面列出的每个脑电图应用程序的研究和商机的未来方向。根据我们的调查,对基于机器学习的脑电图应用程序的更多研究将导致与脑电图相关的更强大的市场。越来越多的公司将使用研究技术并将其应用于现实生活中。随着与EEG相关的市场的增长,与EEG相关的设备将收集更多的脑电图数据,并且将有更多的EEG数据供研究人员在他们的研究中使用,以作为一个良性周期。我们的市场分析表明,在上面列出的六个应用程序中使用脑电图数据和机器学习有关的研究指向脑电图生态系统和机器学习世界的增长和发展的明确趋势。
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