我们研究了$ k $武装的决斗匪徒问题,这是传统的多武器匪徒问题的一种变体,其中以成对比较的形式获得了反馈。以前的学习算法专注于$ \ textit {完全自适应} $设置,在每次比较后,算法可以进行更新。 “批处理”决斗匪徒问题是由Web搜索排名和推荐系统等大规模应用程序激励的,在这种应用程序中执行顺序更新可能是不可行的。在这项工作中,我们要问:$ \ textit {是否只使用几个自适应回合有解决方案,该回合与$ k $ armed的决斗匪徒的最佳顺序算法的渐近后悔界限?} $? \ textit {在condorcet条件下} $,这是$ k $武装的决斗匪徒问题的标准设置。我们获得$ O(k^2 \ log^2(k)) + O(k \ log(t))$的渐近遗憾地平线。我们的遗憾界限几乎与在Condorcet条件下完全顺序环境中已知的最佳后悔界限相匹配。最后,在各种现实世界数据集的计算实验中,我们观察到使用$ o(\ log(t))$ rounds的算法与完全顺序的算法(使用$ t $ rounds)的性能几乎相同。
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机器人仿真一直是数据驱动的操作任务的重要工具。但是,大多数现有的仿真框架都缺乏与触觉传感器的物理相互作用的高效和准确模型,也没有逼真的触觉模拟。这使得基于触觉的操纵任务的SIM转交付仍然具有挑战性。在这项工作中,我们通过建模接触物理学来整合机器人动力学和基于视觉的触觉传感器的模拟。该触点模型使用机器人最终效应器上的模拟接触力来告知逼真的触觉输出。为了消除SIM到真实传输差距,我们使用现实世界数据校准了机器人动力学,接触模型和触觉光学模拟器的物理模拟器,然后我们在零摄像机上演示了系统的有效性 - 真实掌握稳定性预测任务,在各种对象上,我们达到平均准确性为90.7%。实验揭示了将我们的模拟框架应用于更复杂的操纵任务的潜力。我们在https://github.com/cmurobotouch/taxim/tree/taxim-robot上开放仿真框架。
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图形上的分层聚类是数据挖掘和机器学习中的一项基本任务,并在系统发育学,社交网络分析和信息检索等领域中进行了应用。具体而言,我们考虑了由于Dasgupta引起的层次聚类的最近普及的目标函数。以前(大约)最小化此目标函数的算法需要线性时间/空间复杂性。在许多应用程序中,底层图的大小可能很大,即使使用线性时间/空间算法,也可以在计算上具有挑战性。结果,人们对设计只能使用sublinear资源执行全局计算的算法有浓厚的兴趣。这项工作的重点是在三个经过良好的sublinear计算模型下研究大量图的层次聚类,分别侧重于时空,时间和通信,作为要优化的主要资源:(1)(动态)流模型。边缘作为流,(2)查询模型表示,其中使用邻居和度查询查询图形,(3)MPC模型,其中图边缘通过通信通道连接的几台机器进行了分区。我们在上面的所有三个模型中设计用于层次聚类的sublinear算法。我们算法结果的核心是图表中的剪切方面的视图,这使我们能够使用宽松的剪刀示意图进行分层聚类,同时仅引入目标函数中的较小失真。然后,我们的主要算法贡献是如何在查询模型和MPC模型中有效地构建所需形式的切割稀疏器。我们通过建立几乎匹配的下限来补充我们的算法结果,该界限排除了在每个模型中设计更好的算法的可能性。
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We introduce Argoverse 2 (AV2) - a collection of three datasets for perception and forecasting research in the self-driving domain. The annotated Sensor Dataset contains 1,000 sequences of multimodal data, encompassing high-resolution imagery from seven ring cameras, and two stereo cameras in addition to lidar point clouds, and 6-DOF map-aligned pose. Sequences contain 3D cuboid annotations for 26 object categories, all of which are sufficiently-sampled to support training and evaluation of 3D perception models. The Lidar Dataset contains 20,000 sequences of unlabeled lidar point clouds and map-aligned pose. This dataset is the largest ever collection of lidar sensor data and supports self-supervised learning and the emerging task of point cloud forecasting. Finally, the Motion Forecasting Dataset contains 250,000 scenarios mined for interesting and challenging interactions between the autonomous vehicle and other actors in each local scene. Models are tasked with the prediction of future motion for "scored actors" in each scenario and are provided with track histories that capture object location, heading, velocity, and category. In all three datasets, each scenario contains its own HD Map with 3D lane and crosswalk geometry - sourced from data captured in six distinct cities. We believe these datasets will support new and existing machine learning research problems in ways that existing datasets do not. All datasets are released under the CC BY-NC-SA 4.0 license.
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Parkinson's disease is marked by altered and increased firing characteristics of pathological oscillations in the brain. In other words, it causes abnormal synchronous oscillations and suppression during neurological processing. In order to examine and regulate the synchronization and pathological oscillations in motor circuits, deep brain stimulators (DBS) are used. Although machine learning methods have been applied for the investigation of suppression, these models require large amounts of training data and computational power, both of which pose challenges to resource-constrained DBS. This research proposes a novel reinforcement learning (RL) framework for suppressing the synchronization in neuronal activity during episodes of neurological disorders with less power consumption. The proposed RL algorithm comprises an ensemble of a temporal representation of stimuli and a twin-delayed deep deterministic (TD3) policy gradient algorithm. We quantify the stability of the proposed framework to noise and reduced synchrony using RL for three pathological signaling regimes: regular, chaotic, and bursting, and further eliminate the undesirable oscillations. Furthermore, metrics such as evaluation rewards, energy supplied to the ensemble, and the mean point of convergence were used and compared to other RL algorithms, specifically the Advantage actor critic (A2C), the Actor critic with Kronecker-featured trust region (ACKTR), and the Proximal policy optimization (PPO).
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Problem statement: Standardisation of AI fairness rules and benchmarks is challenging because AI fairness and other ethical requirements depend on multiple factors such as context, use case, type of the AI system, and so on. In this paper, we elaborate that the AI system is prone to biases at every stage of its lifecycle, from inception to its usage, and that all stages require due attention for mitigating AI bias. We need a standardised approach to handle AI fairness at every stage. Gap analysis: While AI fairness is a hot research topic, a holistic strategy for AI fairness is generally missing. Most researchers focus only on a few facets of AI model-building. Peer review shows excessive focus on biases in the datasets, fairness metrics, and algorithmic bias. In the process, other aspects affecting AI fairness get ignored. The solution proposed: We propose a comprehensive approach in the form of a novel seven-layer model, inspired by the Open System Interconnection (OSI) model, to standardise AI fairness handling. Despite the differences in the various aspects, most AI systems have similar model-building stages. The proposed model splits the AI system lifecycle into seven abstraction layers, each corresponding to a well-defined AI model-building or usage stage. We also provide checklists for each layer and deliberate on potential sources of bias in each layer and their mitigation methodologies. This work will facilitate layer-wise standardisation of AI fairness rules and benchmarking parameters.
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Supervised approaches generally rely on majority-based labels. However, it is hard to achieve high agreement among annotators in subjective tasks such as hate speech detection. Existing neural network models principally regard labels as categorical variables, while ignoring the semantic information in diverse label texts. In this paper, we propose AnnoBERT, a first-of-its-kind architecture integrating annotator characteristics and label text with a transformer-based model to detect hate speech, with unique representations based on each annotator's characteristics via Collaborative Topic Regression (CTR) and integrate label text to enrich textual representations. During training, the model associates annotators with their label choices given a piece of text; during evaluation, when label information is not available, the model predicts the aggregated label given by the participating annotators by utilising the learnt association. The proposed approach displayed an advantage in detecting hate speech, especially in the minority class and edge cases with annotator disagreement. Improvement in the overall performance is the largest when the dataset is more label-imbalanced, suggesting its practical value in identifying real-world hate speech, as the volume of hate speech in-the-wild is extremely small on social media, when compared with normal (non-hate) speech. Through ablation studies, we show the relative contributions of annotator embeddings and label text to the model performance, and tested a range of alternative annotator embeddings and label text combinations.
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Dense retrievers have made significant strides in obtaining state-of-the-art results on text retrieval and open-domain question answering (ODQA). Yet most of these achievements were made possible with the help of large annotated datasets, unsupervised learning for dense retrieval models remains an open problem. In this work, we explore two categories of methods for creating pseudo query-document pairs, named query extraction (QExt) and transferred query generation (TQGen), to augment the retriever training in an annotation-free and scalable manner. Specifically, QExt extracts pseudo queries by document structures or selecting salient random spans, and TQGen utilizes generation models trained for other NLP tasks (e.g., summarization) to produce pseudo queries. Extensive experiments show that dense retrievers trained with individual augmentation methods can perform comparably well with multiple strong baselines, and combining them leads to further improvements, achieving state-of-the-art performance of unsupervised dense retrieval on both BEIR and ODQA datasets.
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Active target sensing is the task of discovering and classifying an unknown number of targets in an environment and is critical in search-and-rescue missions. This paper develops a deep reinforcement learning approach to plan informative trajectories that increase the likelihood for an uncrewed aerial vehicle (UAV) to discover missing targets. Our approach efficiently (1) explores the environment to discover new targets, (2) exploits its current belief of the target states and incorporates inaccurate sensor models for high-fidelity classification, and (3) generates dynamically feasible trajectories for an agile UAV by employing a motion primitive library. Extensive simulations on randomly generated environments show that our approach is more efficient in discovering and classifying targets than several other baselines. A unique characteristic of our approach, in contrast to heuristic informative path planning approaches, is that it is robust to varying amounts of deviations of the prior belief from the true target distribution, thereby alleviating the challenge of designing heuristics specific to the application conditions.
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We study the sample complexity of reducing reinforcement learning to a sequence of empirical risk minimization problems over the policy space. Such reductions-based algorithms exhibit local convergence in the function space, as opposed to the parameter space for policy gradient algorithms, and thus are unaffected by the possibly non-linear or discontinuous parameterization of the policy class. We propose a variance-reduced variant of Conservative Policy Iteration that improves the sample complexity of producing a $\varepsilon$-functional local optimum from $O(\varepsilon^{-4})$ to $O(\varepsilon^{-3})$. Under state-coverage and policy-completeness assumptions, the algorithm enjoys $\varepsilon$-global optimality after sampling $O(\varepsilon^{-2})$ times, improving upon the previously established $O(\varepsilon^{-3})$ sample requirement.
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