许多支付平台持有大规模的营销活动,为鼓励用户通过他们的申请进行奖励。为了最大限度地提高投资回报,在两阶段程序中通常会解决激励拨款。在训练响应估计模型以估计用户的移动支付概率(MPP)之后,应用线性编程过程来获得最佳激励分配。然而,由先前偏置分配策略生成的训练集中的大量偏置数据导致偏置估计。此偏差劣化响应模型的性能并误导线性编程过程,显着降低了所产生的分配策略的性能。为了克服这种障碍,我们提出了偏置校正对抗性网络。我们的方法利用了在全随机分配策略下获得的一小集非偏见数据来培训一个无偏的模型,然后使用它来减少对抗性学习的偏差。离线和在线实验结果表明,我们的方法优于最先进的方法,并显着提高了现实世界营销活动中所产生的分配政策的绩效。
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尽管在一般强化学习(RL)中建立了良好的建立,但很少在受约束的RL(CRL)中探索基于价值的方法,因为它们无法找到可以在多个动作中随机进行随机的策略的能力。为了将基于价值的方法应用于CRL,最新的游戏理论方法采用了混合策略,该策略将一组精心生成的策略之间随机进行随机,以收敛到所需的约束可满足的策略。但是,这些方法需要存储大量的政策,这不是政策效率的,并且可能会在约束深度RL中产生过高的记忆成本。为了解决这个问题,我们提出了一种替代方法。我们的方法首先将CRL重新制定为等效距离优化问题。使用专门设计的线性优化Oracle,我们得出了一个元叠层,该元值使用任何现成的RL算法和任何条件梯度(CG)型算法作为子例程来求解它。然后,我们提出了CG型算法的新变体,该变体概括了最小范数(MNP)方法。所提出的方法与现有游戏理论方法的收敛速率相匹配,并实现了最差的最佳政策效率。导航任务上的实验表明,我们的方法将记忆成本降低了一个数量级,同时达到了更好的性能,并证明了其有效性和效率。
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我们开发了一个新颖的框架,将稀疏集团拉索的正规化者添加到深度学习中的自适应优化者家族中,例如动量,亚当,亚当,阿姆斯格拉德,阿德哈西亚人,并创建了新的优化者,这些优化者被称为群体动量,命名因此,Adagrad小组,亚当集团,Amsgrad集团和Adahessian集团等。我们基于原始偶的方法在随机凸设置中建立理论上证明的收敛保证。我们评估了新优化器对具有最先进的深度学习模型的三个大型现实广告单击数据集的正则效应。实验结果表明,与使用幅度修剪方法的后处理过程相比,模型的性能可以在相同的稀疏度水平上显着提高。此外,与没有幅度修剪的情况相比,我们的方法可以实现极高的稀疏性,并具有明显的更好或高度竞争性的性能。
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汤普森采样(TS)是解决上下文多武装强盗问题最有效的算法之一。在本文中,我们提出了一种新的算法,称为神经汤普森采样,这适应了深度神经网络,用于勘探和剥削。在我们的算法的核心是一种新的奖励的后分布,其平均值是神经网络近似器,并且其方差建立在相应神经网络的神经切线特征上。我们证明,如果底层奖励函数是有界的,则可以保证所提出的算法来实现$ \ mathcal {o}(t ^ {1/2})$的累积遗憾,它与其他上下文强盗算法的遗憾匹配总轮数量$ t $。各种数据集中其他基准强盗算法的实验比较证实了我们的理论。
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Large training data and expensive model tweaking are standard features of deep learning for images. As a result, data owners often utilize cloud resources to develop large-scale complex models, which raises privacy concerns. Existing solutions are either too expensive to be practical or do not sufficiently protect the confidentiality of data and models. In this paper, we study and compare novel \emph{image disguising} mechanisms, DisguisedNets and InstaHide, aiming to achieve a better trade-off among the level of protection for outsourced DNN model training, the expenses, and the utility of data. DisguisedNets are novel combinations of image blocktization, block-level random permutation, and two block-level secure transformations: random multidimensional projection (RMT) and AES pixel-level encryption (AES). InstaHide is an image mixup and random pixel flipping technique \cite{huang20}. We have analyzed and evaluated them under a multi-level threat model. RMT provides a better security guarantee than InstaHide, under the Level-1 adversarial knowledge with well-preserved model quality. In contrast, AES provides a security guarantee under the Level-2 adversarial knowledge, but it may affect model quality more. The unique features of image disguising also help us to protect models from model-targeted attacks. We have done an extensive experimental evaluation to understand how these methods work in different settings for different datasets.
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A storyboard is a roadmap for video creation which consists of shot-by-shot images to visualize key plots in a text synopsis. Creating video storyboards however remains challenging which not only requires association between high-level texts and images, but also demands for long-term reasoning to make transitions smooth across shots. In this paper, we propose a new task called Text synopsis to Video Storyboard (TeViS) which aims to retrieve an ordered sequence of images to visualize the text synopsis. We construct a MovieNet-TeViS benchmark based on the public MovieNet dataset. It contains 10K text synopses each paired with keyframes that are manually selected from corresponding movies by considering both relevance and cinematic coherence. We also present an encoder-decoder baseline for the task. The model uses a pretrained vision-and-language model to improve high-level text-image matching. To improve coherence in long-term shots, we further propose to pre-train the decoder on large-scale movie frames without text. Experimental results demonstrate that our proposed model significantly outperforms other models to create text-relevant and coherent storyboards. Nevertheless, there is still a large gap compared to human performance suggesting room for promising future work.
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Solving real-world optimal control problems are challenging tasks, as the system dynamics can be highly non-linear or including nonconvex objectives and constraints, while in some cases the dynamics are unknown, making it hard to numerically solve the optimal control actions. To deal with such modeling and computation challenges, in this paper, we integrate Neural Networks with the Pontryagin's Minimum Principle (PMP), and propose a computationally efficient framework NN-PMP. The resulting controller can be implemented for systems with unknown and complex dynamics. It can not only utilize the accurate surrogate models parameterized by neural networks, but also efficiently recover the optimality conditions along with the optimal action sequences via PMP conditions. A toy example on a nonlinear Martian Base operation along with a real-world lossy energy storage arbitrage example demonstrates our proposed NN-PMP is a general and versatile computation tool for finding optimal solutions. Compared with solutions provided by the numerical optimization solver with approximated linear dynamics, NN-PMP achieves more efficient system modeling and higher performance in terms of control objectives.
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Learning policies from fixed offline datasets is a key challenge to scale up reinforcement learning (RL) algorithms towards practical applications. This is often because off-policy RL algorithms suffer from distributional shift, due to mismatch between dataset and the target policy, leading to high variance and over-estimation of value functions. In this work, we propose variance regularization for offline RL algorithms, using stationary distribution corrections. We show that by using Fenchel duality, we can avoid double sampling issues for computing the gradient of the variance regularizer. The proposed algorithm for offline variance regularization (OVAR) can be used to augment any existing offline policy optimization algorithms. We show that the regularizer leads to a lower bound to the offline policy optimization objective, which can help avoid over-estimation errors, and explains the benefits of our approach across a range of continuous control domains when compared to existing state-of-the-art algorithms.
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The task of reconstructing 3D human motion has wideranging applications. The gold standard Motion capture (MoCap) systems are accurate but inaccessible to the general public due to their cost, hardware and space constraints. In contrast, monocular human mesh recovery (HMR) methods are much more accessible than MoCap as they take single-view videos as inputs. Replacing the multi-view Mo- Cap systems with a monocular HMR method would break the current barriers to collecting accurate 3D motion thus making exciting applications like motion analysis and motiondriven animation accessible to the general public. However, performance of existing HMR methods degrade when the video contains challenging and dynamic motion that is not in existing MoCap datasets used for training. This reduces its appeal as dynamic motion is frequently the target in 3D motion recovery in the aforementioned applications. Our study aims to bridge the gap between monocular HMR and multi-view MoCap systems by leveraging information shared across multiple video instances of the same action. We introduce the Neural Motion (NeMo) field. It is optimized to represent the underlying 3D motions across a set of videos of the same action. Empirically, we show that NeMo can recover 3D motion in sports using videos from the Penn Action dataset, where NeMo outperforms existing HMR methods in terms of 2D keypoint detection. To further validate NeMo using 3D metrics, we collected a small MoCap dataset mimicking actions in Penn Action,and show that NeMo achieves better 3D reconstruction compared to various baselines.
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Late-life depression (LLD) is a highly prevalent mood disorder occurring in older adults and is frequently accompanied by cognitive impairment (CI). Studies have shown that LLD may increase the risk of Alzheimer's disease (AD). However, the heterogeneity of presentation of geriatric depression suggests that multiple biological mechanisms may underlie it. Current biological research on LLD progression incorporates machine learning that combines neuroimaging data with clinical observations. There are few studies on incident cognitive diagnostic outcomes in LLD based on structural MRI (sMRI). In this paper, we describe the development of a hybrid representation learning (HRL) framework for predicting cognitive diagnosis over 5 years based on T1-weighted sMRI data. Specifically, we first extract prediction-oriented MRI features via a deep neural network, and then integrate them with handcrafted MRI features via a Transformer encoder for cognitive diagnosis prediction. Two tasks are investigated in this work, including (1) identifying cognitively normal subjects with LLD and never-depressed older healthy subjects, and (2) identifying LLD subjects who developed CI (or even AD) and those who stayed cognitively normal over five years. To the best of our knowledge, this is among the first attempts to study the complex heterogeneous progression of LLD based on task-oriented and handcrafted MRI features. We validate the proposed HRL on 294 subjects with T1-weighted MRIs from two clinically harmonized studies. Experimental results suggest that the HRL outperforms several classical machine learning and state-of-the-art deep learning methods in LLD identification and prediction tasks.
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