在本文中,我们提出了一种序列到集合的方法,该方法可以根据最大似然转换任何序列生成模型,转换为设置生成模型,我们可以在其中评估任何集合的效用/概率。设计了一种有效的重要性采样算法,以应对学习序列到集合模型的计算挑战。我们提出GRU2SET,这是我们的序列到集合方法的实例,并采用著名的GRU模型作为序列生成模型。为了进一步获得集合的置换不变表示,我们设计了SETNN模型,这也是序列到集合模型的实例。我们模型的直接应用是从电子商务订单集合中学习订单/集合,这是许多重要的运营决策中的重要步骤,例如快速交付的库存安排。基于与大型集合相比,小型集合通常更易于学习的直觉,我们提出了一个大小偏见的技巧,可以帮助学习相对于$ \ ell_1 $ distance评估度量的更好的设置分布。两个电子商务订单数据集TMALL和HKTVMALL用于进行广泛的实验以显示我们的模型的有效性。实验结果表明,与基准相比,我们的模型可以从订单数据中学习更好的设置/顺序分布。此外,无论我们使用哪种模型,应用大小偏见的技巧总是可以提高从数据中学到的集合分布的质量。
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项目反应理论(IRT)是一个无处不在的模型,可以根据他们对问题的回答理解人类行为和态度。大型现代数据集为捕捉人类行为的更多细微差别提供了机会,从而有可能改善心理测量模型,从而改善科学理解和公共政策。但是,尽管较大的数据集允许采用更灵活的方法,但许多用于拟合IRT模型的当代算法也可能具有禁止现实世界应用的巨大计算需求。为了解决这种瓶颈,我们引入了IRT的变异贝叶斯推理算法,并表明它在不牺牲准确性的情况下快速可扩展。将此方法应用于认知科学和教育的五个大规模项目响应数据集中,比替代推理算法更高的对数可能性和更高的准确性。然后,使用这种新的推论方法,我们将IRT概括为具有表现力的贝叶斯响应模型,利用深度学习的最新进展来捕获具有神经网络的非线性项目特征曲线(ICC)。使用TIMSS的特定级数学测试,我们显示我们的非线性IRT模型可以捕获有趣的不对称ICC。该算法实现是开源的,易于使用。
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象征性的AI社区越来越多地试图在神经符号结构中接受机器学习,但由于文化障碍,仍在挣扎。为了打破障碍,这份相当有思想的个人备忘录试图解释和纠正统计,机器学习和深入学习的惯例,从局外人的角度进行深入学习。它提供了一个分步协议,用于设计一个机器学习系统,该系统满足符号AI社区认真对待所必需的最低理论保证,即,它讨论“在哪些条件下,我们可以停止担心和接受统计机器学习。 “一些亮点:大多数教科书都是为计划专门研究STAT/ML/DL的人编写的,应该接受术语。该备忘录适用于经验丰富的象征研究人员,他们听到了很多嗡嗡声,但仍然不确定和持怀疑态度。有关STAT/ML/DL的信息目前太分散或嘈杂而无法投资。此备忘录优先考虑紧凑性,并特别注意与象征性范式相互共鸣的概念。我希望这份备忘录能节省时间。它优先考虑一般数学建模,并且不讨论任何特定的函数近似器,例如神经网络(NNS),SVMS,决策树等。它可以对校正开放。将此备忘录视为与博客文章相似的内容,采用有关Arxiv的论文的形式。
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Pre-publication draft of a book to be published byMorgan & Claypool publishers. Unedited version released with permission. All relevant copyrights held by the author and publisher extend to this pre-publication draft.
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Influence Maximization (IM) is a classical combinatorial optimization problem, which can be widely used in mobile networks, social computing, and recommendation systems. It aims at selecting a small number of users such that maximizing the influence spread across the online social network. Because of its potential commercial and academic value, there are a lot of researchers focusing on studying the IM problem from different perspectives. The main challenge comes from the NP-hardness of the IM problem and \#P-hardness of estimating the influence spread, thus traditional algorithms for overcoming them can be categorized into two classes: heuristic algorithms and approximation algorithms. However, there is no theoretical guarantee for heuristic algorithms, and the theoretical design is close to the limit. Therefore, it is almost impossible to further optimize and improve their performance. With the rapid development of artificial intelligence, the technology based on Machine Learning (ML) has achieved remarkable achievements in many fields. In view of this, in recent years, a number of new methods have emerged to solve combinatorial optimization problems by using ML-based techniques. These methods have the advantages of fast solving speed and strong generalization ability to unknown graphs, which provide a brand-new direction for solving combinatorial optimization problems. Therefore, we abandon the traditional algorithms based on iterative search and review the recent development of ML-based methods, especially Deep Reinforcement Learning, to solve the IM problem and other variants in social networks. We focus on summarizing the relevant background knowledge, basic principles, common methods, and applied research. Finally, the challenges that need to be solved urgently in future IM research are pointed out.
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当前独立于域的经典计划者需要问题域和实例作为输入的符号模型,从而导致知识采集瓶颈。同时,尽管深度学习在许多领域都取得了重大成功,但知识是在与符号系统(例如计划者)不兼容的亚符号表示中编码的。我们提出了Latplan,这是一种无监督的建筑,结合了深度学习和经典计划。只有一组未标记的图像对,显示了环境中允许的过渡子集(训练输入),Latplan学习了环境的完整命题PDDL动作模型。稍后,当给出代表初始状态和目标状态(计划输入)的一对图像时,Latplan在符号潜在空间中找到了目标状态的计划,并返回可视化的计划执行。我们使用6个计划域的基于图像的版本来评估LATPLAN:8个插头,15个式嘴,Blockworld,Sokoban和两个LightsOut的变体。
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已经引入了生成流量网络(GFlowNETS)作为在主动学习背景下采样多样化候选的方法,具有培训目标,其使它们与给定奖励功能成比例地进行比例。在本文中,我们显示了许多额外的GFLOWN的理论特性。它们可用于估计联合概率分布和一些变量未指定的相应边际分布,并且特别感兴趣地,可以代表像集合和图形的复合对象的分布。 Gflownets摊销了通常通过计算昂贵的MCMC方法在单个但训练有素的生成通行证中进行的工作。它们还可用于估计分区功能和自由能量,给定子集(子图)的超标(超图)的条件概率,以及给定集合(图)的所有超标仪(超图)的边际分布。我们引入了熵和相互信息估计的变体,从帕累托前沿采样,与奖励最大化策略的连接,以及随机环境的扩展,连续动作和模块化能量功能。
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期望 - 最大化(EM)算法是一种简单的元叠加,当观察到的数据中缺少测量值或数据由可观察到的数据组成时,它已多年来用作统计推断的方法。它的一般属性进行了充分的研究,而且还有无数方法将其应用于个人问题。在本文中,我们介绍了$ em $ $ and算法,EM算法的信息几何公式及其扩展和应用程序以及各种问题。具体而言,我们将看到,可以制定一个异常稳定推理算法,用于计算通道容量的算法,概率单纯性的参数估计方法,特定的多变量分析方法,例如概率模型中的主要组件分析和模态回归中的主成分分析,基质分解和学习生成模型,这些模型最近从几何学角度引起了深度学习的关注。
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顺序推荐是推荐系统的广泛流行的主题。现有的作品有助于提高基于各种方法的顺序推荐系统的预测能力,例如经常性网络和自我关注机制。然而,他们未能发现和区分项目之间的各种关系,这可能是激励用户行为的潜在因素。在本文中,我们提出了一个边缘增强的全面解散图神经网络(EGD-GNN)模型,以捕获全局项目表示和本地用户意图学习项目之间的关系信息。在全球级别,我们通过所有序列构建全局链接图来模拟项目关系。然后,频道感知的解缠绕学习层被设计成将边缘信息分解为不同的信道,这可以聚合以将目标项从其邻居表示。在本地层面,我们应用一个变化的自动编码器框架来学习用户在当前序列上的意图。我们在三个现实世界数据集中评估我们提出的方法。实验结果表明,我们的模型可以通过最先进的基线获得至关重要的改进,能够区分项目特征。
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Normalizing flows provide a general mechanism for defining expressive probability distributions, only requiring the specification of a (usually simple) base distribution and a series of bijective transformations. There has been much recent work on normalizing flows, ranging from improving their expressive power to expanding their application. We believe the field has now matured and is in need of a unified perspective. In this review, we attempt to provide such a perspective by describing flows through the lens of probabilistic modeling and inference. We place special emphasis on the fundamental principles of flow design, and discuss foundational topics such as expressive power and computational trade-offs. We also broaden the conceptual framing of flows by relating them to more general probability transformations. Lastly, we summarize the use of flows for tasks such as generative modeling, approximate inference, and supervised learning.
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学习神经集功能在许多应用中越来越重要,例如产品推荐和AI辅助药物发现中的复合选择。在功能值Oracle下,大多数现有的作品研究方法学方法学方法学都需要昂贵的监督信号。这使得仅在最佳子集(OS)Oracle下仅进行弱监督的应用程序使其不切实际,而研究的研究令人惊讶地忽略了。在这项工作中,我们提出了一个原则上但实用的最大似然学习框架,称为等效性,该框架同时满足OS ORACLE下的以下学习设置功能:i)置入了模型的设定质量函数的置换率; ii)许可不同地面套件; iii)最低先验;和iv)可伸缩性。我们框架的主要组成部分涉及:对设定质量函数的基于能量的处理,深空式体系结构来处理置换不变性,平均场变异推理及其摊销变体。由于这些高级体系结构的优雅组合,对三个现实世界应用的实证研究(包括亚马逊产品推荐,设置异常检测和虚拟筛选的复合选择)表明,EquivSet的表现优于基本线的大幅度。
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The success of machine learning algorithms generally depends on data representation, and we hypothesize that this is because different representations can entangle and hide more or less the different explanatory factors of variation behind the data. Although specific domain knowledge can be used to help design representations, learning with generic priors can also be used, and the quest for AI is motivating the design of more powerful representation-learning algorithms implementing such priors. This paper reviews recent work in the area of unsupervised feature learning and deep learning, covering advances in probabilistic models, auto-encoders, manifold learning, and deep networks. This motivates longer-term unanswered questions about the appropriate objectives for learning good representations, for computing representations (i.e., inference), and the geometrical connections between representation learning, density estimation and manifold learning.
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这项正在进行的工作旨在为统计学习提供统一的介绍,从诸如GMM和HMM等经典模型到现代神经网络(如VAE和扩散模型)缓慢地构建。如今,有许多互联网资源可以孤立地解释这一点或新的机器学习算法,但是它们并没有(也不能在如此简短的空间中)将这些算法彼此连接起来,或者与统计模型的经典文献相连现代算法出现了。同样明显缺乏的是一个单一的符号系统,尽管对那些已经熟悉材料的人(如这些帖子的作者)不满意,但对新手的入境造成了重大障碍。同样,我的目的是将各种模型(尽可能)吸收到一个用于推理和学习的框架上,表明(以及为什么)如何以最小的变化将一个模型更改为另一个模型(其中一些是新颖的,另一些是文献中的)。某些背景当然是必要的。我以为读者熟悉基本的多变量计算,概率和统计以及线性代数。这本书的目标当然不是​​完整性,而是从基本知识到过去十年中极强大的新模型的直线路径或多或少。然后,目标是补充而不是替换,诸如Bishop的\ emph {模式识别和机器学习}之类的综合文本,该文本现在已经15岁了。
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Aiming at exploiting the rich information in user behaviour sequences, sequential recommendation has been widely adopted in real-world recommender systems. However, current methods suffer from the following issues: 1) sparsity of user-item interactions, 2) uncertainty of sequential records, 3) long-tail items. In this paper, we propose to incorporate contrastive learning into the framework of Variational AutoEncoders to address these challenges simultaneously. Firstly, we introduce ContrastELBO, a novel training objective that extends the conventional single-view ELBO to two-view case and theoretically builds a connection between VAE and contrastive learning from a two-view perspective. Then we propose Contrastive Variational AutoEncoder (ContrastVAE in short), a two-branched VAE model with contrastive regularization as an embodiment of ContrastELBO for sequential recommendation. We further introduce two simple yet effective augmentation strategies named model augmentation and variational augmentation to create a second view of a sequence and thus making contrastive learning possible. Experiments on four benchmark datasets demonstrate the effectiveness of ContrastVAE and the proposed augmentation methods. Codes are available at https://github.com/YuWang-1024/ContrastVAE
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Outstanding achievements of graph neural networks for spatiotemporal time series analysis show that relational constraints introduce an effective inductive bias into neural forecasting architectures. Often, however, the relational information characterizing the underlying data-generating process is unavailable and the practitioner is left with the problem of inferring from data which relational graph to use in the subsequent processing stages. We propose novel, principled - yet practical - probabilistic score-based methods that learn the relational dependencies as distributions over graphs while maximizing end-to-end the performance at task. The proposed graph learning framework is based on consolidated variance reduction techniques for Monte Carlo score-based gradient estimation, is theoretically grounded, and, as we show, effective in practice. In this paper, we focus on the time series forecasting problem and show that, by tailoring the gradient estimators to the graph learning problem, we are able to achieve state-of-the-art performance while controlling the sparsity of the learned graph and the computational scalability. We empirically assess the effectiveness of the proposed method on synthetic and real-world benchmarks, showing that the proposed solution can be used as a stand-alone graph identification procedure as well as a graph learning component of an end-to-end forecasting architecture.
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统计模型是机器学习的核心,具有广泛适用性,跨各种下游任务。模型通常由通过最大似然估计从数据估计的自由参数控制。但是,当面对现实世界数据集时,许多模型运行到一个关键问题:它们是在完全观察到的数据方面配制的,而在实践中,数据集会困扰缺失数据。来自不完整数据的统计模型估计理论在概念上类似于潜在变量模型的估计,其中存在强大的工具,例如变分推理(VI)。然而,与标准潜在变量模型相比,具有不完整数据的参数估计通常需要估计缺失变量的指数 - 许多条件分布,因此使标准的VI方法是棘手的。通过引入变分Gibbs推理(VGI),是一种新的通用方法来解决这个差距,以估计来自不完整数据的统计模型参数。我们在一组合成和实际估算任务上验证VGI,从不完整的数据中估算重要的机器学习模型,VAE和标准化流程。拟议的方法,同时通用,实现比现有的特定模型特定估计方法竞争或更好的性能。
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变异推理(VI)的核心原理是将计算复杂后概率密度计算的统计推断问题转换为可拖动的优化问题。该属性使VI比几种基于采样的技术更快。但是,传统的VI算法无法扩展到大型数据集,并且无法轻易推断出越野数据点,而无需重新运行优化过程。该领域的最新发展,例如随机,黑框和摊销VI,已帮助解决了这些问题。如今,生成的建模任务广泛利用摊销VI来实现其效率和可扩展性,因为它利用参数化函数来学习近似的后验密度参数。在本文中,我们回顾了各种VI技术的数学基础,以构成理解摊销VI的基础。此外,我们还概述了最近解决摊销VI问题的趋势,例如摊销差距,泛化问题,不一致的表示学习和后验崩溃。最后,我们分析了改善VI优化的替代差异度量。
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Deep learning has been shown to be successful in a number of domains, ranging from acoustics, images, to natural language processing. However, applying deep learning to the ubiquitous graph data is non-trivial because of the unique characteristics of graphs. Recently, substantial research efforts have been devoted to applying deep learning methods to graphs, resulting in beneficial advances in graph analysis techniques. In this survey, we comprehensively review the different types of deep learning methods on graphs. We divide the existing methods into five categories based on their model architectures and training strategies: graph recurrent neural networks, graph convolutional networks, graph autoencoders, graph reinforcement learning, and graph adversarial methods. We then provide a comprehensive overview of these methods in a systematic manner mainly by following their development history. We also analyze the differences and compositions of different methods. Finally, we briefly outline the applications in which they have been used and discuss potential future research directions.
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Making sense of multiple modalities can yield a more comprehensive description of real-world phenomena. However, learning the co-representation of diverse modalities is still a long-standing endeavor in emerging machine learning applications and research. Previous generative approaches for multimodal input approximate a joint-modality posterior by uni-modality posteriors as product-of-experts (PoE) or mixture-of-experts (MoE). We argue that these approximations lead to a defective bound for the optimization process and loss of semantic connection among modalities. This paper presents a novel variational method on sets called the Set Multimodal VAE (SMVAE) for learning a multimodal latent space while handling the missing modality problem. By modeling the joint-modality posterior distribution directly, the proposed SMVAE learns to exchange information between multiple modalities and compensate for the drawbacks caused by factorization. In public datasets of various domains, the experimental results demonstrate that the proposed method is applicable to order-agnostic cross-modal generation while achieving outstanding performance compared to the state-of-the-art multimodal methods. The source code for our method is available online https://anonymous.4open.science/r/SMVAE-9B3C/.
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这是一门专门针对STEM学生开发的介绍性机器学习课程。我们的目标是为有兴趣的读者提供基础知识,以在自己的项目中使用机器学习,并将自己熟悉术语作为进一步阅读相关文献的基础。在这些讲义中,我们讨论受监督,无监督和强化学习。注释从没有神经网络的机器学习方法的说明开始,例如原理分析,T-SNE,聚类以及线性回归和线性分类器。我们继续介绍基本和先进的神经网络结构,例如密集的进料和常规神经网络,经常性的神经网络,受限的玻尔兹曼机器,(变性)自动编码器,生成的对抗性网络。讨论了潜在空间表示的解释性问题,并使用梦和对抗性攻击的例子。最后一部分致力于加强学习,我们在其中介绍了价值功能和政策学习的基本概念。
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