DeepMind的游戏理论与多代理团队研究多学科学习的几个方面,从计算近似值到游戏理论中的基本概念,再到在富裕的空间环境中模拟社会困境,并在困难的团队协调任务中培训3-D类人动物。我们小组的一个签名目的是使用DeepMind在DeepMind中提供的资源和专业知识,以深入强化学习来探索复杂环境中的多代理系统,并使用这些基准来提高我们的理解。在这里,我们总结了我们团队的最新工作,并提出了一种分类法,我们认为这重点介绍了多代理研究中许多重要的开放挑战。
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大图通常出现在社交网络,知识图,推荐系统,生命科学和决策问题中。通过其高级别属性总结大图有助于解决这些设置中的问题。在光谱聚类中,我们旨在确定大多数边缘落在簇内的节点簇,而在簇之间只有很少的边缘。此任务对于许多下游应用和探索性分析很重要。光谱聚类的核心步骤是执行相应图的拉普拉斯矩阵(或等效地,奇异值分解,SVD)的特征分类。迭代奇异值分解方法的收敛取决于给定矩阵的光谱的特征,即连续特征值之间的差异。对于对应于群集图的图形的图形拉普拉斯,特征值将是非负的,但很小(小于$ 1 $)的减慢收敛性。本文引入了一种可行的方法,用于扩张光谱以加速SVD求解器,然后又是光谱群集。这是通过对矩阵操作的多项式近似来实现的,矩阵操作有利地改变矩阵的光谱而不更改其特征向量。实验表明,这种方法显着加速了收敛,我们解释了如何并行化和随机近似于可用的计算。
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广义特征值问题(GEP)是数值线性代数中的基本概念。它捕获了许多经典的机器学习问题的解决方案,例如规范相关分析,独立组件分析,部分最小二乘,线性判别分析,主要组件,后继功能等。尽管如此,在处理大量数据集时,大多数通用求解器都非常昂贵,而研究则集中在为特定问题实例找到有效的解决方案。在这项工作中,我们开发了顶级$ K $ GEP的游戏理论公式,其NASH平衡是一组广义特征向量。我们还提出了一种可行的算法,并保证了与NASH的渐近收敛。当前的最新方法需要$ \ MATHCAL {O}(d^2k)$复杂性,当尺寸数量($ d $)较大时,这是高昂的昂贵。我们展示了如何实现$ \ MATHCAL {O}(dk)$复杂性,比例缩放到数据集$ 100 \ times $ $比先前方法评估的$。从经验上讲,我们证明我们的算法能够解决各种GEP问题实例,包括对神经网络激活的大规模分析。
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深度加强学习(RL)的最新进展导致许多2人零和游戏中的相当大的进展,如去,扑克和星际争霸。这种游戏的纯粹对抗性质允许概念上简单地应用R1方法。然而,现实世界的设置是许多代理商,代理交互是复杂的共同利益和竞争方面的混合物。我们认为外交,一个旨在突出由多种代理交互导致的困境的7人棋盘游戏。它还具有大型组合动作空间和同时移动,这对RL算法具有具有挑战性。我们提出了一个简单但有效的近似最佳响应操作员,旨在处理大型组合动作空间并同时移动。我们还介绍了一系列近似虚构游戏的政策迭代方法。通过这些方法,我们成功地将RL申请到外交:我们认为我们的代理商令人信服地令人信服地表明,游戏理论均衡分析表明新过程产生了一致的改进。
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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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Feature selection helps reduce data acquisition costs in ML, but the standard approach is to train models with static feature subsets. Here, we consider the dynamic feature selection (DFS) problem where a model sequentially queries features based on the presently available information. DFS is often addressed with reinforcement learning (RL), but we explore a simpler approach of greedily selecting features based on their conditional mutual information. This method is theoretically appealing but requires oracle access to the data distribution, so we develop a learning approach based on amortized optimization. The proposed method is shown to recover the greedy policy when trained to optimality and outperforms numerous existing feature selection methods in our experiments, thus validating it as a simple but powerful approach for this problem.
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Remote sensing of the Earth's surface water is critical in a wide range of environmental studies, from evaluating the societal impacts of seasonal droughts and floods to the large-scale implications of climate change. Consequently, a large literature exists on the classification of water from satellite imagery. Yet, previous methods have been limited by 1) the spatial resolution of public satellite imagery, 2) classification schemes that operate at the pixel level, and 3) the need for multiple spectral bands. We advance the state-of-the-art by 1) using commercial imagery with panchromatic and multispectral resolutions of 30 cm and 1.2 m, respectively, 2) developing multiple fully convolutional neural networks (FCN) that can learn the morphological features of water bodies in addition to their spectral properties, and 3) FCN that can classify water even from panchromatic imagery. This study focuses on rivers in the Arctic, using images from the Quickbird, WorldView, and GeoEye satellites. Because no training data are available at such high resolutions, we construct those manually. First, we use the RGB, and NIR bands of the 8-band multispectral sensors. Those trained models all achieve excellent precision and recall over 90% on validation data, aided by on-the-fly preprocessing of the training data specific to satellite imagery. In a novel approach, we then use results from the multispectral model to generate training data for FCN that only require panchromatic imagery, of which considerably more is available. Despite the smaller feature space, these models still achieve a precision and recall of over 85%. We provide our open-source codes and trained model parameters to the remote sensing community, which paves the way to a wide range of environmental hydrology applications at vastly superior accuracies and 2 orders of magnitude higher spatial resolution than previously possible.
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Many real-world reinforcement learning tasks require control of complex dynamical systems that involve both costly data acquisition processes and large state spaces. In cases where the transition dynamics can be readily evaluated at specified states (e.g., via a simulator), agents can operate in what is often referred to as planning with a \emph{generative model}. We propose the AE-LSVI algorithm for best-policy identification, a novel variant of the kernelized least-squares value iteration (LSVI) algorithm that combines optimism with pessimism for active exploration (AE). AE-LSVI provably identifies a near-optimal policy \emph{uniformly} over an entire state space and achieves polynomial sample complexity guarantees that are independent of the number of states. When specialized to the recently introduced offline contextual Bayesian optimization setting, our algorithm achieves improved sample complexity bounds. Experimentally, we demonstrate that AE-LSVI outperforms other RL algorithms in a variety of environments when robustness to the initial state is required.
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Natural language interaction is a promising direction for democratizing 3D shape design. However, existing methods for text-driven 3D shape editing face challenges in producing decoupled, local edits to 3D shapes. We address this problem by learning disentangled latent representations that ground language in 3D geometry. To this end, we propose a complementary tool set including a novel network architecture, a disentanglement loss, and a new editing procedure. Additionally, to measure edit locality, we define a new metric that we call part-wise edit precision. We show that our method outperforms existing SOTA methods by 20% in terms of edit locality, and up to 6.6% in terms of language reference resolution accuracy. Our work suggests that by solely disentangling language representations, downstream 3D shape editing can become more local to relevant parts, even if the model was never given explicit part-based supervision.
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Neural networks have revolutionized the area of artificial intelligence and introduced transformative applications to almost every scientific field and industry. However, this success comes at a great price; the energy requirements for training advanced models are unsustainable. One promising way to address this pressing issue is by developing low-energy neuromorphic hardware that directly supports the algorithm's requirements. The intrinsic non-volatility, non-linearity, and memory of spintronic devices make them appealing candidates for neuromorphic devices. Here we focus on the reservoir computing paradigm, a recurrent network with a simple training algorithm suitable for computation with spintronic devices since they can provide the properties of non-linearity and memory. We review technologies and methods for developing neuromorphic spintronic devices and conclude with critical open issues to address before such devices become widely used.
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