自Reddi等人以来。 2018年指出了亚当的分歧问题,已经设计了许多新变体以获得融合。但是,香草·亚当(Vanilla Adam)仍然非常受欢迎,并且在实践中效果很好。为什么理论和实践之间存在差距?我们指出,理论和实践的设置之间存在不匹配:Reddi等。 2018年选择亚当的超参数后选择问题,即$(\ beta_1,\ beta_2)$;虽然实际应用通常首先解决问题,然后调整$(\ beta_1,\ beta_2)$。由于这一观察,我们猜想只有当我们改变选择问题和超参数的顺序时,理论上的经验收敛才能是合理的。在这项工作中,我们确认了这一猜想。我们证明,当$ \ beta_2 $很大时,$ \ beta_1 <\ sqrt {\ beta_2} <1 $,Adam收集到关键点附近。邻居的大小是随机梯度方差的命题。在额外的条件(强烈生长条件)下,亚当收敛到关键点。随着$ \ beta_2 $的增加,我们的收敛结果可以覆盖[0,1)$中的任何$ \ beta_1 \,包括$ \ beta_1 = 0.9 $,这是深度学习库中的默认设置。我们的结果表明,亚当可以在广泛的超参数下收敛,而无需对其更新规则进行任何修改。据我们所知,我们是第一个证明这一结果的人,而没有强有力的假设,例如有限梯度。当$ \ beta_2 $很小时,我们进一步指出了一个$(\ beta_1,\ beta_2)$的大区域,亚当可以在其中偏离无限。我们的差异结果考虑与我们的收敛结果相同的设置,表明在增加$ \ beta_2 $时从差异到收敛的相变。这些正面和负面的结果可以提供有关如何调整亚当超级参数的建议。
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在本文中,我们应对PCA:异质性的重大挑战。当从不同趋势的不同来源收集数据的同时仍具有一致性时,提取共享知识的同时保留每个来源的独特功能至关重要。为此,我们提出了个性化的PCA(PERPCA),该PCA(PERPCA)使用相互正交的全球和本地主要组件来编码唯一的和共享的功能。我们表明,在轻度条件下,即使协方差矩阵截然不同,也可以通过约束优化问题来识别和恢复独特的和共享的特征。此外,我们设计了一种完全由分布式stiefel梯度下降来解决问题的完全联合算法。该算法引入了一组新的操作,称为通用缩回,以处理正交性约束,并且仅要求跨来源共享全局PC。我们证明了在合适的假设下算法的线性收敛。全面的数值实验突出了PERPCA在特征提取和异质数据集预测方面的出色性能。作为将共享和唯一功能从异质数据集解除共享和独特功能的系统方法,PERPCA在几种任务中找到了应用程序,包括视频细分,主题提取和分布式聚类。
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事情互联网(物联网)正处于重大范式转变的边缘。在未来的IOT系统中,IOFT,云将被人群代替模型训练被带到边缘的人群,允许IOT设备协作提取知识并构建智能分析/型号,同时保持本地存储的个人数据。这种范式转变被IOT设备的计算能力巨大增加以及分散和隐私保留模型培训的最近进步,作为联合学习(FL)。本文为IOFT提供了愿景,并系统概述当前努力实现这一愿景。具体而言,我们首先介绍IOFT的定义特征,并讨论了三维内部的分散推断的流动方法,机会和挑战:(i)全局模型,最大化跨所有IOT设备的实用程序,(ii)个性化模型所有设备的借款强度都保留了自己的模型,(iii)一个迅速适应新设备或学习任务的元学习模型。通过描述Ioft通过域专家镜头重塑不同行业的愿景和挑战来结束。这些行业包括制造,运输,能源,医疗保健,质量和可靠性,商业和计算。
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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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Image Virtual try-on aims at replacing the cloth on a personal image with a garment image (in-shop clothes), which has attracted increasing attention from the multimedia and computer vision communities. Prior methods successfully preserve the character of clothing images, however, occlusion remains a pernicious effect for realistic virtual try-on. In this work, we first present a comprehensive analysis of the occlusions and categorize them into two aspects: i) Inherent-Occlusion: the ghost of the former cloth still exists in the try-on image; ii) Acquired-Occlusion: the target cloth warps to the unreasonable body part. Based on the in-depth analysis, we find that the occlusions can be simulated by a novel semantically-guided mixup module, which can generate semantic-specific occluded images that work together with the try-on images to facilitate training a de-occlusion try-on (DOC-VTON) framework. Specifically, DOC-VTON first conducts a sharpened semantic parsing on the try-on person. Aided by semantics guidance and pose prior, various complexities of texture are selectively blending with human parts in a copy-and-paste manner. Then, the Generative Module (GM) is utilized to take charge of synthesizing the final try-on image and learning to de-occlusion jointly. In comparison to the state-of-the-art methods, DOC-VTON achieves better perceptual quality by reducing occlusion effects.
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Dynamic treatment regimes assign personalized treatments to patients sequentially over time based on their baseline information and time-varying covariates. In mobile health applications, these covariates are typically collected at different frequencies over a long time horizon. In this paper, we propose a deep spectral Q-learning algorithm, which integrates principal component analysis (PCA) with deep Q-learning to handle the mixed frequency data. In theory, we prove that the mean return under the estimated optimal policy converges to that under the optimal one and establish its rate of convergence. The usefulness of our proposal is further illustrated via simulations and an application to a diabetes dataset.
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As natural language processing (NLP) for gender bias becomes a significant interdisciplinary topic, the prevalent data-driven techniques such as large-scale language models suffer from data inadequacy and biased corpus, especially for languages with insufficient resources such as Chinese. To this end, we propose a Chinese cOrpus foR Gender bIas Probing and Mitigation CORGI-PM, which contains 32.9k sentences with high-quality labels derived by following an annotation scheme specifically developed for gender bias in the Chinese context. Moreover, we address three challenges for automatic textual gender bias mitigation, which requires the models to detect, classify, and mitigate textual gender bias. We also conduct experiments with state-of-the-art language models to provide baselines. To our best knowledge, CORGI-PM is the first sentence-level Chinese corpus for gender bias probing and mitigation.
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Off-policy evaluation (OPE) is a method for estimating the return of a target policy using some pre-collected observational data generated by a potentially different behavior policy. In some cases, there may be unmeasured variables that can confound the action-reward or action-next-state relationships, rendering many existing OPE approaches ineffective. This paper develops an instrumental variable (IV)-based method for consistent OPE in confounded Markov decision processes (MDPs). Similar to single-stage decision making, we show that IV enables us to correctly identify the target policy's value in infinite horizon settings as well. Furthermore, we propose an efficient and robust value estimator and illustrate its effectiveness through extensive simulations and analysis of real data from a world-leading short-video platform.
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Off-Policy evaluation (OPE) is concerned with evaluating a new target policy using offline data generated by a potentially different behavior policy. It is critical in a number of sequential decision making problems ranging from healthcare to technology industries. Most of the work in existing literature is focused on evaluating the mean outcome of a given policy, and ignores the variability of the outcome. However, in a variety of applications, criteria other than the mean may be more sensible. For example, when the reward distribution is skewed and asymmetric, quantile-based metrics are often preferred for their robustness. In this paper, we propose a doubly-robust inference procedure for quantile OPE in sequential decision making and study its asymptotic properties. In particular, we propose utilizing state-of-the-art deep conditional generative learning methods to handle parameter-dependent nuisance function estimation. We demonstrate the advantages of this proposed estimator through both simulations and a real-world dataset from a short-video platform. In particular, we find that our proposed estimator outperforms classical OPE estimators for the mean in settings with heavy-tailed reward distributions.
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The ability to jointly learn from multiple modalities, such as text, audio, and visual data, is a defining feature of intelligent systems. While there have been promising advances in designing neural networks to harness multimodal data, the enormous success of data augmentation currently remains limited to single-modality tasks like image classification. Indeed, it is particularly difficult to augment each modality while preserving the overall semantic structure of the data; for example, a caption may no longer be a good description of an image after standard augmentations have been applied, such as translation. Moreover, it is challenging to specify reasonable transformations that are not tailored to a particular modality. In this paper, we introduce LeMDA, Learning Multimodal Data Augmentation, an easy-to-use method that automatically learns to jointly augment multimodal data in feature space, with no constraints on the identities of the modalities or the relationship between modalities. We show that LeMDA can (1) profoundly improve the performance of multimodal deep learning architectures, (2) apply to combinations of modalities that have not been previously considered, and (3) achieve state-of-the-art results on a wide range of applications comprised of image, text, and tabular data.
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