We present a method for controlling a swarm using its spectral decomposition -- that is, by describing the set of trajectories of a swarm in terms of a spatial distribution throughout the operational domain -- guaranteeing scale invariance with respect to the number of agents both for computation and for the operator tasked with controlling the swarm. We use ergodic control, decentralized across the network, for implementation. In the DARPA OFFSET program field setting, we test this interface design for the operator using the STOMP interface -- the same interface used by Raytheon BBN throughout the duration of the OFFSET program. In these tests, we demonstrate that our approach is scale-invariant -- the user specification does not depend on the number of agents; it is persistent -- the specification remains active until the user specifies a new command; and it is real-time -- the user can interact with and interrupt the swarm at any time. Moreover, we show that the spectral/ergodic specification of swarm behavior degrades gracefully as the number of agents goes down, enabling the operator to maintain the same approach as agents become disabled or are added to the network. We demonstrate the scale-invariance and dynamic response of our system in a field relevant simulator on a variety of tactical scenarios with up to 50 agents. We also demonstrate the dynamic response of our system in the field with a smaller team of agents. Lastly, we make the code for our system available.

In this paper, we address the problem of safe trajectory planning for autonomous search and exploration in constrained, cluttered environments. Guaranteeing safe navigation is a challenging problem that has garnered significant attention. This work contributes a method that generates guaranteed safety-critical search trajectories in a cluttered environment. Our approach integrates safety-critical constraints using discrete control barrier functions (DCBFs) with ergodic trajectory optimization to enable safe exploration. Ergodic trajectory optimization plans continuous exploratory trajectories that guarantee full coverage of a space. We demonstrate through simulated and experimental results on a drone that our approach is able to generate trajectories that enable safe and effective exploration. Furthermore, we show the efficacy of our approach for safe exploration of real-world single- and multi- drone platforms.

功能配准算法表示点云为函数（例如，空间占用场），避免了常规最小二乘Quares注册算法中不可靠的对应估计。但是，现有的功能注册算法在计算上很昂贵。此外，在基于CAD模型的对象本地化等任务中，必须使用未知量表的注册能力，但是功能注册中没有这种支持。在这项工作中，我们提出了一种比例不变的线性时间复杂性功能配准算法。我们通过使用正顺序基函数在功能之间的L2距离之间有效地近似实现线性时间复杂性。正统基函数的使用导致与最小二乘配准兼容的公式。受益于最小二乘的公式，我们使用翻译反转不变测量的理论来解除尺度估计，从而实现规模不变的注册。我们在标准的3D注册基准上评估了所提出的算法，称为FLS（功能最小二乘），显示FLS的数量级比最先进的功能配准算法快，而无需损害准确性和鲁棒性。 FLS还胜过基于最小二乘的最小二乘注册算法，其精度和鲁棒性具有已知和未知量表。最后，我们证明将FLS应用于具有不同密度和部分重叠的寄存点云，同一类别中不同对象的点云以及带有嘈杂RGB-D测量值的真实世界对象的点云。

在不同情况下，机器人有可能执行搜索各种应用程序。我们的工作是由人道主义助理和灾难救济（HADR）激发的，在存在冲突的标准，目标和信息的情况下，找到生命的迹象通常至关重要。我们认为，厄运搜索可以提供一个框架来利用可用信息，并为HADR等应用程序探索新信息，尤其是在时间本质上。千古搜索算法规划轨迹，使得在一个地区所花费的时间与该地区的信息量成正比，并且能够自然平衡剥削（近视搜索高信息搜索区域）和探索（访问搜索空间的所有位置以获取新的信息）。现有的Ergodic搜索算法以及其他基于信息的方法通常仅使用单个信息图考虑搜索。但是，在许多情况下，使用多个编码不同类型相关信息的多个信息图很常见。当前的厄运搜索方法没有同时的能力，也不具有平衡信息优先级的方法。这使我们提出了一个多目标的千古搜索（MOES）问题，旨在找到所谓的帕累托最佳解决方案，目的是为人类的决策者提供各种解决方案，这些解决方案在相互矛盾的标准之间进行贸易。为了有效地解决MOE，我们开发了一个称为顺序局部Ergodic搜索（SLE）的框架，该框架将MOES问题转换为“重量空间覆盖率”问题。它利用了厄隆搜索方法的最新进展以及局部优化的想法，以有效地近似帕累托最佳前沿。我们的数值结果表明，SLE的运行速度明显快于基线方法。

缩放多智能体增强学习的卓越障碍之一是为大量代理商分配给个别代理的行动。在本文中，我们通过呼叫\ yrest {部分奖励去耦}（prd）的方法来解决这一信用分配问题，该方法试图将大型合作多代理RL问题分解成涉及代理子集的解耦子问题，从而简化了信用分配。我们经验证明使用PRD在演员 - 批评算法中分解RL问题导致较低的差异策略梯度估计，这提高了各种其他跨越多个代理RL任务的数据效率，学习稳定性和渐近性能。演员 - 评论家方法。此外，我们还将我们的反事实多代理政策梯度（COMA），最先进的MARL算法以及经验证明我们的方法通过更好地利用代理商奖励流的信息来实现昏迷状态，以及启用最近的优势估计的进步。

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.

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.

The Government of Kerala had increased the frequency of supply of free food kits owing to the pandemic, however, these items were static and not indicative of the personal preferences of the consumers. This paper conducts a comparative analysis of various clustering techniques on a scaled-down version of a real-world dataset obtained through a conjoint analysis-based survey. Clustering carried out by centroid-based methods such as k means is analyzed and the results are plotted along with SVD, and finally, a conclusion is reached as to which among the two is better. Once the clusters have been formulated, commodities are also decided upon for each cluster. Also, clustering is further enhanced by reassignment, based on a specific cluster loss threshold. Thus, the most efficacious clustering technique for designing a food kit tailored to the needs of individuals is finally obtained.

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.

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.