强化学习中的固有问题是应对不确定要采取的行动(或状态价值)的政策。模型不确定性,更正式地称为认知不确定性,是指超出采样噪声的模型的预期预测误差。在本文中,我们提出了Q值函数中认知不确定性估计的度量,我们将其称为路线上的认知不确定性。我们进一步开发了一种计算其近似上限的方法,我们称之为f值。我们通过实验将后者应用于深Q-Networks(DQN),并表明增强学习中的不确定性估计是学习进步的有用指标。然后,我们提出了一种新的方法,通过从现有(以前学过的或硬编码)的甲骨文政策中学习不确定性的同时,旨在避免在训练过程中避免非生产性的随机操作,从而提高参与者批评算法的样本效率。我们认为这位评论家的信心指导了探索(CCGE)。我们使用我们的F-Value指标在软演奏者(SAC)上实施CCGE,我们将其应用于少数流行的健身环境,并表明它比有限的背景下的香草囊获得了更好的样本效率和全部情节奖励。
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可视化优化景观导致了数字优化的许多基本见解,并对优化技术进行了新的改进。但是,仅在少数狭窄的环境中生成了增强学习优化(“奖励表面”)的目标的可视化。这项工作首次介绍了27个最广泛使用的增强学习环境的奖励表面和相关的可视化。我们还探索了政策梯度方向上的奖励表面,并首次表明许多流行的强化学习环境经常出现“悬崖”(预期回报中突然下降)。我们证明,A2C经常将这些悬崖“脱落”到参数空间的低奖励区域,而PPO避免了它们,这证实了PPO对PPO的流行直觉,以改善以前的方法。我们还引入了一个高度可扩展的库,该库使研究人员将来可以轻松地生成这些可视化。我们的发现提供了新的直觉,以解释现代RL方法的成功和失败,我们的可视化构成了以新颖方式进行强化学习剂的几种失败模式。
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联合机器学习是一种用于训练多个设备模型的技术,而无需在它们之间交换数据。因为数据仍然是每个计算节点的本地,所以联合学习非常适合在仔细控制数据的字段中的使用情况,例如医学,或者具有带宽约束的域。这种方法的一个弱点是大多数联合学习工具依赖于中央服务器来执行工作负载委派并生成单个共享模型。在这里,我们建议一个灵活的框架,用于分散联合学习模式,并提供与Pytorch兼容的开源,参考实现。
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自动驾驶数据集通常是倾斜的,特别是,缺乏距自工载体远距离的物体的训练数据。随着检测到的对象的距离增加,数据的不平衡导致性能下降。在本文中,我们提出了模式识的地面真相抽样,一种数据增强技术,该技术基于LIDAR的特征缩小对象的点云。具体地,我们模拟了用于深度的物体的自然发散点模式变化,以模拟更远的距离。因此,网络具有更多样化的训练示例,并且可以更有效地概括地检测更远的物体。我们评估了使用点删除或扰动方法的现有数据增强技术,并发现我们的方法优于所有这些。此外,我们建议使用相等的元素AP箱,以评估跨距离的3D对象探测器的性能。我们在距离大于25米的距离上的Kitti验证分裂上提高了PV-RCNN对车载PV-RCNN的性能。
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小型太阳能光伏(PV)阵列中电网的有效集成计划需要访问高质量的数据:单个太阳能PV阵列的位置和功率容量。不幸的是,不存在小型太阳能光伏的国家数据库。那些确实有限的空间分辨率,通常汇总到州或国家一级。尽管已经发布了几种有希望的太阳能光伏检测方法,但根据研究,研究这些模型的性能通常是高度异质的。这些方法对能源评估的实际应用的比较变得具有挑战性,可能意味着报告的绩效评估过于乐观。异质性有多种形式,我们在这项工作中探讨了每种形式:空间聚集的水平,地面真理的验证,培训和验证数据集的不一致以及培训的位置和传感器的多样性程度和验证数据始发。对于每个人,我们都会讨论文献中的新兴实践,以解决它们或暗示未来研究的方向。作为调查的一部分,我们评估了两个大区域的太阳PV识别性能。我们的发现表明,由于验证过程中的共同局限性,从卫星图像对太阳PV自动识别的传统绩效评估可能是乐观的。这项工作的收获旨在为能源研究人员和专业人员提供自动太阳能光伏评估技术的大规模实用应用。
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Designing experiments often requires balancing between learning about the true treatment effects and earning from allocating more samples to the superior treatment. While optimal algorithms for the Multi-Armed Bandit Problem (MABP) provide allocation policies that optimally balance learning and earning, they tend to be computationally expensive. The Gittins Index (GI) is a solution to the MABP that can simultaneously attain optimality and computationally efficiency goals, and it has been recently used in experiments with Bernoulli and Gaussian rewards. For the first time, we present a modification of the GI rule that can be used in experiments with exponentially-distributed rewards. We report its performance in simulated 2- armed and 3-armed experiments. Compared to traditional non-adaptive designs, our novel GI modified design shows operating characteristics comparable in learning (e.g. statistical power) but substantially better in earning (e.g. direct benefits). This illustrates the potential that designs using a GI approach to allocate participants have to improve participant benefits, increase efficiencies, and reduce experimental costs in adaptive multi-armed experiments with exponential rewards.
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Modelling and forecasting real-life human behaviour using online social media is an active endeavour of interest in politics, government, academia, and industry. Since its creation in 2006, Twitter has been proposed as a potential laboratory that could be used to gauge and predict social behaviour. During the last decade, the user base of Twitter has been growing and becoming more representative of the general population. Here we analyse this user base in the context of the 2021 Mexican Legislative Election. To do so, we use a dataset of 15 million election-related tweets in the six months preceding election day. We explore different election models that assign political preference to either the ruling parties or the opposition. We find that models using data with geographical attributes determine the results of the election with better precision and accuracy than conventional polling methods. These results demonstrate that analysis of public online data can outperform conventional polling methods, and that political analysis and general forecasting would likely benefit from incorporating such data in the immediate future. Moreover, the same Twitter dataset with geographical attributes is positively correlated with results from official census data on population and internet usage in Mexico. These findings suggest that we have reached a period in time when online activity, appropriately curated, can provide an accurate representation of offline behaviour.
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Existing federated classification algorithms typically assume the local annotations at every client cover the same set of classes. In this paper, we aim to lift such an assumption and focus on a more general yet practical non-IID setting where every client can work on non-identical and even disjoint sets of classes (i.e., client-exclusive classes), and the clients have a common goal which is to build a global classification model to identify the union of these classes. Such heterogeneity in client class sets poses a new challenge: how to ensure different clients are operating in the same latent space so as to avoid the drift after aggregation? We observe that the classes can be described in natural languages (i.e., class names) and these names are typically safe to share with all parties. Thus, we formulate the classification problem as a matching process between data representations and class representations and break the classification model into a data encoder and a label encoder. We leverage the natural-language class names as the common ground to anchor the class representations in the label encoder. In each iteration, the label encoder updates the class representations and regulates the data representations through matching. We further use the updated class representations at each round to annotate data samples for locally-unaware classes according to similarity and distill knowledge to local models. Extensive experiments on four real-world datasets show that the proposed method can outperform various classical and state-of-the-art federated learning methods designed for learning with non-IID data.
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This is paper for the smooth function approximation by neural networks (NN). Mathematical or physical functions can be replaced by NN models through regression. In this study, we get NNs that generate highly accurate and highly smooth function, which only comprised of a few weight parameters, through discussing a few topics about regression. First, we reinterpret inside of NNs for regression; consequently, we propose a new activation function--integrated sigmoid linear unit (ISLU). Then special charateristics of metadata for regression, which is different from other data like image or sound, is discussed for improving the performance of neural networks. Finally, the one of a simple hierarchical NN that generate models substituting mathematical function is presented, and the new batch concept ``meta-batch" which improves the performance of NN several times more is introduced. The new activation function, meta-batch method, features of numerical data, meta-augmentation with metaparameters, and a structure of NN generating a compact multi-layer perceptron(MLP) are essential in this study.
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The existing methods for video anomaly detection mostly utilize videos containing identifiable facial and appearance-based features. The use of videos with identifiable faces raises privacy concerns, especially when used in a hospital or community-based setting. Appearance-based features can also be sensitive to pixel-based noise, straining the anomaly detection methods to model the changes in the background and making it difficult to focus on the actions of humans in the foreground. Structural information in the form of skeletons describing the human motion in the videos is privacy-protecting and can overcome some of the problems posed by appearance-based features. In this paper, we present a survey of privacy-protecting deep learning anomaly detection methods using skeletons extracted from videos. We present a novel taxonomy of algorithms based on the various learning approaches. We conclude that skeleton-based approaches for anomaly detection can be a plausible privacy-protecting alternative for video anomaly detection. Lastly, we identify major open research questions and provide guidelines to address them.
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