Offline policy evaluation is a fundamental statistical problem in reinforcement learning that involves estimating the value function of some decision-making policy given data collected by a potentially different policy. In order to tackle problems with complex, high-dimensional observations, there has been significant interest from theoreticians and practitioners alike in understanding the possibility of function approximation in reinforcement learning. Despite significant study, a sharp characterization of when we might expect offline policy evaluation to be tractable, even in the simplest setting of linear function approximation, has so far remained elusive, with a surprising number of strong negative results recently appearing in the literature. In this work, we identify simple control-theoretic and linear-algebraic conditions that are necessary and sufficient for classical methods, in particular Fitted Q-iteration (FQI) and least squares temporal difference learning (LSTD), to succeed at offline policy evaluation. Using this characterization, we establish a precise hierarchy of regimes under which these estimators succeed. We prove that LSTD works under strictly weaker conditions than FQI. Furthermore, we establish that if a problem is not solvable via LSTD, then it cannot be solved by a broad class of linear estimators, even in the limit of infinite data. Taken together, our results provide a complete picture of the behavior of linear estimators for offline policy evaluation, unify previously disparate analyses of canonical algorithms, and provide significantly sharper notions of the underlying statistical complexity of offline policy evaluation.
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How would you fairly evaluate two multi-object tracking algorithms (i.e. trackers), each one employing a different object detector? Detectors keep improving, thus trackers can make less effort to estimate object states over time. Is it then fair to compare a new tracker employing a new detector with another tracker using an old detector? In this paper, we propose a novel performance measure, named Tracking Effort Measure (TEM), to evaluate trackers that use different detectors. TEM estimates the improvement that the tracker does with respect to its input data (i.e. detections) at frame level (intra-frame complexity) and sequence level (inter-frame complexity). We evaluate TEM over well-known datasets, four trackers and eight detection sets. Results show that, unlike conventional tracking evaluation measures, TEM can quantify the effort done by the tracker with a reduced correlation on the input detections. Its implementation is publicly available online at https://github.com/vpulab/MOT-evaluation.
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Plastic shopping bags that get carried away from the side of roads and tangled on cotton plants can end up at cotton gins if not removed before the harvest. Such bags may not only cause problem in the ginning process but might also get embodied in cotton fibers reducing its quality and marketable value. Therefore, it is required to detect, locate, and remove the bags before cotton is harvested. Manually detecting and locating these bags in cotton fields is labor intensive, time-consuming and a costly process. To solve these challenges, we present application of four variants of YOLOv5 (YOLOv5s, YOLOv5m, YOLOv5l and YOLOv5x) for detecting plastic shopping bags using Unmanned Aircraft Systems (UAS)-acquired RGB (Red, Green, and Blue) images. We also show fixed effect model tests of color of plastic bags as well as YOLOv5-variant on average precision (AP), mean average precision (mAP@50) and accuracy. In addition, we also demonstrate the effect of height of plastic bags on the detection accuracy. It was found that color of bags had significant effect (p < 0.001) on accuracy across all the four variants while it did not show any significant effect on the AP with YOLOv5m (p = 0.10) and YOLOv5x (p = 0.35) at 95% confidence level. Similarly, YOLOv5-variant did not show any significant effect on the AP (p = 0.11) and accuracy (p = 0.73) of white bags, but it had significant effects on the AP (p = 0.03) and accuracy (p = 0.02) of brown bags including on the mAP@50 (p = 0.01) and inference speed (p < 0.0001). Additionally, height of plastic bags had significant effect (p < 0.0001) on overall detection accuracy. The findings reported in this paper can be useful in speeding up removal of plastic bags from cotton fields before harvest and thereby reducing the amount of contaminants that end up at cotton gins.
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Predictive monitoring is a subfield of process mining that aims to predict how a running case will unfold in the future. One of its main challenges is forecasting the sequence of activities that will occur from a given point in time -- suffix prediction -- . Most approaches to the suffix prediction problem learn to predict the suffix by learning how to predict the next activity only, not learning from the whole suffix during the training phase. This paper proposes a novel architecture based on an encoder-decoder model with an attention mechanism that decouples the representation learning of the prefixes from the inference phase, predicting only the activities of the suffix. During the inference phase, this architecture is extended with a heuristic search algorithm that improves the selection of the activity for each index of the suffix. Our approach has been tested using 12 public event logs against 6 different state-of-the-art proposals, showing that it significantly outperforms these proposals.
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我们提出了一个将张量网络(TN)方法与加固学习(RL)集成的框架,以解决动态优化任务。我们考虑RL Actor-Critic方法,这是一种解决RL问题的无模型方法,并将TNS作为其政策和价值功能的近似值。我们的“带有张量网络的参与者评论”(ACTEN)方法特别适合具有大型和可分解状态和动作空间的问题。为了说明ACTEN的适用性,我们解决了在两个范式随机模型中对稀有轨迹进行指定的艰巨任务,East模型的眼镜和不对称的简单排除过程(ASEP),后者由于对其他方法特别具有挑战性缺乏详细的平衡。在与现有的RL方法中进一步集成的巨大潜力,此处介绍的方法对物理应用程序的应用和多代理RL问题都有希望。
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尽管沟通延迟可能会破坏多种系统,但大多数现有的多基因轨迹计划者都缺乏解决此问题的策略。最先进的方法通常采用完美的通信环境,这在现实世界实验中几乎是现实的。本文介绍了强大的Mader(RMADER),这是一个分散的异步多轨迹计划者,可以处理代理商之间的通信延迟。通过广播新优化的轨迹和忠实的轨迹,并执行延迟检查步骤,Rmader即使在通信延迟下也能够保证安全。Rmader通过广泛的仿真和硬件飞行实验得到了验证,并获得了100%的无碰撞轨迹生成成功率,表现优于最先进的方法。
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在机器学习中,对神经网络集合(NNE)(NNE)引起了新的兴趣,从而从一组较小的模型(而不是从单个较大的模型)中获得了预测作为汇总的预测。在这里,我们展示了如何使用随机系统中稀有轨迹的技术来定义和训练NNE。我们根据模型参数的轨迹定义一个NNE,在简单的,离散的时间,扩散动力学下,并通过将这些轨迹偏向较小的时间整合损失来训练NNE,并由适当的计数领域控制,这些领域的作用是超参数。我们证明了该技术在一系列简单监督的学习任务上的生存能力。与更常规的基于梯度的方法相比,我们讨论了轨迹采样方法的潜在优势。
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Boll Weevil(Anthonomus Grandis L.)是一种严重的害虫,主要以棉花为食。由于亚热带气候条件,在德克萨斯州的下里奥格兰德山谷等地方,棉花植物可以全年生长,因此,收获期间上一个季节的剩下的种子可以在玉米中的旋转中继续生长(Zea Mays L.)和高粱(高粱双色L.)。这些野性或志愿棉花(VC)植物到达Pinhead平方阶段(5-6叶阶段)可以充当Boll Weevil Pest的宿主。得克萨斯州的鲍尔象鼻虫根除计划(TBWEP)雇用人们在道路或田野侧面生长的风险投资和消除旋转作物的田间生长,但在田野中生长的植物仍未被发现。在本文中,我们证明了基于您的计算机视觉(CV)算法的应用,仅在三个不同的生长阶段(V3,V6)(V3,V6)中检测出在玉米场中生长的VC植物,以检测在玉米场中生长的VC植物的应用。使用无人飞机系统(UAS)遥感图像。使用Yolov5(S,M,L和X)的所有四个变体,并根据分类精度,平均平均精度(MAP)和F1得分进行比较。发现Yolov5s可以在玉米的V6阶段检测到最大分类精度为98%,地图为96.3%,而Yolov5s和Yolov5m的地图为96.3%,而Yolov5m的分类精度为85%,Yolov5m和Yolov5m的分类准确性最小,而Yolov5L的分类精度最少。在VT阶段,在尺寸416 x 416像素的图像上为86.5%。开发的CV算法有可能有效地检测和定位在玉米场中间生长的VC植物,并加快TBWEP的管理方面。
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在执行现实生活过程中,计划或意外的变化是常见的。检测这些更改是优化运行此类过程的组织的性能的必要条件。最先进的大多数算法都集中在突然变化的检测上,抛开其他类型的变化。在本文中,我们将专注于自动检测渐进漂移,这是一种特殊的变化类型,其中两个模型的情况在一段时间内重叠。所提出的算法依赖于一致性检查指标来自动检测变化,还将这些变化的全自动分类为突然或逐渐分类。该方法已通过一个由120个日志组成的合成数据集进行了验证,该数据集具有不同的变化分布,在检测和分类准确性,延迟和变化区域在比较主要的最新算法方面取得更好的结果。
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为了控制棉花场中的鲍尔象鼻虫(Anthonomus Grandis L.)害虫重新感染,目前的志愿棉花(VC)(VC)(gossypium hirsutum L.)植物检测玉米(Zea Mays L.)和Sorghum等旋转作物中的植物检测(高粱双色L.)涉及在田野边缘的手动田地侦察。这导致许多风险植物在田野中间生长仍未被发现,并继续与玉米和高粱并肩生长。当他们到达Pinhead平方阶段(5-6片叶子)时,它们可以充当鲍尔维尔虫害的宿主。因此,需要检测,定位,然后精确地用化学物质进行斑点。在本文中,我们介绍了Yolov5M在放射线和伽马校正的低分辨率(1.2兆像素)的多光谱图像中的应用,以检测和定位在康沃尔场的流苏中间(VT)生长阶段生长的VC植物。我们的结果表明,可以以平均平均精度(地图)为79%,分类精度为78%,大小为1207 x 923像素的分类精度为78%,平均推理速度在NVIDIA上的平均推理速度接近47帧(FPS) NVIDIA JETSON TX2 GPU上的Tesla P100 GPU-16GB和0.4 fps。我们还证明了基于开发的计算机视觉(CV)算法的定制无人飞机系统(UAS)的应用应用程序应用程序,以及如何将其用于近乎实时检测和缓解玉米领域中VC植物的近乎实时检测和缓解为了有效地管理鲍尔象鼻虫害虫。
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