我们考虑在重复的未知游戏中进行规避风险的学习,在这种游戏中,代理商的目标是最大程度地减少其个人产生高成本的风险。具体而言,代理商使用处于风险的条件值(CVAR)作为风险措施,并以每集选定动作的成本值的形式依靠强盗反馈来估算其CVAR值并更新其动作。使用匪徒反馈来估计CVAR的一个主要挑战是,代理只能访问其自身的成本值,但是,这取决于所有代理的行为。为了应对这一挑战,我们提出了一种新的规避风险的学习算法,并利用有关成本价值的完整历史信息。我们表明,该算法实现了子线性的遗憾,并匹配了文献中最著名的算法。我们为欧洲大师游戏提供了数值实验,该游戏表明我们的方法表现优于现有方法。
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本文提出了一类具有多项式非线性的非线性系统的基于数据驱动的集基估计算法。使用系统的输入输出数据,所提出的方法实时计算,保证包含系统状态的集合。尽管假设系统是多项式类型,但不需要知道精确的多项式函数及其系数。为此,估算器依赖于离线和在线阶段。离线阶段利用过去的输入输出数据来估计多项式系统的一组可能的系数。然后,使用该估计的系数和关于系统的侧面信息,在线阶段提供了对状态的集合估计。最后,通过其对SIR(易感,受感染的)的流行病模型的应用来评估所提出的方法。
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This paper considers the distributed online convex optimization problem with time-varying constraints over a network of agents. This is a sequential decision making problem with two sequences of arbitrarily varying convex loss and constraint functions. At each round, each agent selects a decision from the decision set, and then only a portion of the loss function and a coordinate block of the constraint function at this round are privately revealed to this agent. The goal of the network is to minimize the network-wide loss accumulated over time. Two distributed online algorithms with full-information and bandit feedback are proposed. Both dynamic and static network regret bounds are analyzed for the proposed algorithms, and network cumulative constraint violation is used to measure constraint violation, which excludes the situation that strictly feasible constraints can compensate the effects of violated constraints. In particular, we show that the proposed algorithms achieve $\mathcal{O}(T^{\max\{\kappa,1-\kappa\}})$ static network regret and $\mathcal{O}(T^{1-\kappa/2})$ network cumulative constraint violation, where $T$ is the time horizon and $\kappa\in(0,1)$ is a user-defined trade-off parameter. Moreover, if the loss functions are strongly convex, then the static network regret bound can be reduced to $\mathcal{O}(T^{\kappa})$. Finally, numerical simulations are provided to illustrate the effectiveness of the theoretical results.
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数学模型是动态控制系统设计中的基本构件。随着控制系统变得越来越复杂和网络,基于第一原理的方法达到了限制。数据驱动的方法提供了替代方案。但是,在没有结构知识的情况下,这些方法很容易在训练数据中找到虚假的相关性,这可能会妨碍所获得的模型的概括能力。当系统暴露于未知情况时,这可以显着降低控制和预测性能。先前的因果鉴定可以防止这种陷阱。在本文中,我们提出了一种识别控制系统因果结构的方法。我们根据可控性概念设计实验,该概念提供了一种系统的方法来计算输入轨迹,该输入轨迹将系统引导到其状态空间中的特定区域。然后,我们分析从因果推理中利用强大技术的结果数据,并将其扩展到控制系统。此外,我们得出了保证发现系统真正因果结构的条件。在机器人臂上的实验表明,来自现实世界数据和增强的概括能力的可靠因果鉴定。
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ICECUBE是一种用于检测1 GEV和1 PEV之间大气和天体中微子的光学传感器的立方公斤阵列,该阵列已部署1.45 km至2.45 km的南极的冰盖表面以下1.45 km至2.45 km。来自ICE探测器的事件的分类和重建在ICeCube数据分析中起着核心作用。重建和分类事件是一个挑战,这是由于探测器的几何形状,不均匀的散射和冰中光的吸收,并且低于100 GEV的光,每个事件产生的信号光子数量相对较少。为了应对这一挑战,可以将ICECUBE事件表示为点云图形,并将图形神经网络(GNN)作为分类和重建方法。 GNN能够将中微子事件与宇宙射线背景区分开,对不同的中微子事件类型进行分类,并重建沉积的能量,方向和相互作用顶点。基于仿真,我们提供了1-100 GEV能量范围的比较与当前ICECUBE分析中使用的当前最新最大似然技术,包括已知系统不确定性的影响。对于中微子事件分类,与当前的IceCube方法相比,GNN以固定的假阳性速率(FPR)提高了信号效率的18%。另外,GNN在固定信号效率下将FPR的降低超过8(低于半百分比)。对于能源,方向和相互作用顶点的重建,与当前最大似然技术相比,分辨率平均提高了13%-20%。当在GPU上运行时,GNN能够以几乎是2.7 kHz的中位数ICECUBE触发速率的速率处理ICECUBE事件,这打开了在在线搜索瞬态事件中使用低能量中微子的可能性。
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我们介绍了DeepNash,这是一种能够学习从头开始播放不完美的信息游戏策略的自主代理,直到人类的专家级别。 Stratego是人工智能(AI)尚未掌握的少数标志性棋盘游戏之一。这个受欢迎的游戏具有$ 10^{535} $节点的巨大游戏树,即,$ 10^{175} $倍的$倍于GO。它具有在不完美的信息下需要决策的其他复杂性,类似于德克萨斯州Hold'em扑克,该扑克的游戏树较小(以$ 10^{164} $节点为单位)。 Stratego中的决策是在许多离散的动作上做出的,而动作与结果之间没有明显的联系。情节很长,在球员获胜之前经常有数百次动作,而Stratego中的情况则不能像扑克中那样轻松地分解成管理大小的子问题。由于这些原因,Stratego几十年来一直是AI领域的巨大挑战,现有的AI方法几乎没有达到业余比赛水平。 Deepnash使用游戏理论,无模型的深钢筋学习方法,而无需搜索,该方法学会通过自我播放来掌握Stratego。 DeepNash的关键组成部分的正则化NASH Dynamics(R-NAD)算法通过直接修改基础多项式学习动力学来收敛到近似NASH平衡,而不是围绕它“循环”。 Deepnash在Stratego中击败了现有的最先进的AI方法,并在Gravon Games平台上获得了年度(2022年)和历史前3名,并与人类专家竞争。
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我们为具有有界过程和测量噪声的未知线性系统模型提供了一种强大的数据驱动控制方案。不取决于传统预测控制中的系统模型,提出了利用数据驱动的可达区域的控制器。数据驱动的可到达区域基于矩阵Zonotope递归,并且基于仅系统的轨迹的噪声输入输出数据来计算。我们假设测量和过程噪声包含在有界集中。虽然我们承担了这些界限的知识,但假设了关于噪声的统计特性的知识。在无噪声情况下,我们证明所呈现的纯粹数据驱动的控制方案导致等效的闭环行为到标称模型预测控制方案。在测量和过程噪声的情况下,我们提出的方案保证了强大的约束满足感,这在安全关键型应用中至关重要。数值实验表明了所提出的数据驱动控制器与基于模型的控制方案相比的有效性。
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Making histopathology image classifiers robust to a wide range of real-world variability is a challenging task. Here, we describe a candidate deep learning solution for the Mitosis Domain Generalization Challenge 2022 (MIDOG) to address the problem of generalization for mitosis detection in images of hematoxylin-eosin-stained histology slides under high variability (scanner, tissue type and species variability). Our approach consists in training a rotation-invariant deep learning model using aggressive data augmentation with a training set enriched with hard negative examples and automatically selected negative examples from the unlabeled part of the challenge dataset. To optimize the performance of our models, we investigated a hard negative mining regime search procedure that lead us to train our best model using a subset of image patches representing 19.6% of our training partition of the challenge dataset. Our candidate model ensemble achieved a F1-score of .697 on the final test set after automated evaluation on the challenge platform, achieving the third best overall score in the MIDOG 2022 Challenge.
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Reading comprehension of legal text can be a particularly challenging task due to the length and complexity of legal clauses and a shortage of expert-annotated datasets. To address this challenge, we introduce the Merger Agreement Understanding Dataset (MAUD), an expert-annotated reading comprehension dataset based on the American Bar Association's 2021 Public Target Deal Points Study, with over 39,000 examples and over 47,000 total annotations. Our fine-tuned Transformer baselines show promising results, with models performing well above random on most questions. However, on a large subset of questions, there is still room for significant improvement. As the only expert-annotated merger agreement dataset, MAUD is valuable as a benchmark for both the legal profession and the NLP community.
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Real-life tools for decision-making in many critical domains are based on ranking results. With the increasing awareness of algorithmic fairness, recent works have presented measures for fairness in ranking. Many of those definitions consider the representation of different ``protected groups'', in the top-$k$ ranked items, for any reasonable $k$. Given the protected groups, confirming algorithmic fairness is a simple task. However, the groups' definitions may be unknown in advance. In this paper, we study the problem of detecting groups with biased representation in the top-$k$ ranked items, eliminating the need to pre-define protected groups. The number of such groups possible can be exponential, making the problem hard. We propose efficient search algorithms for two different fairness measures: global representation bounds, and proportional representation. Then we propose a method to explain the bias in the representations of groups utilizing the notion of Shapley values. We conclude with an experimental study, showing the scalability of our approach and demonstrating the usefulness of the proposed algorithms.
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