我们考虑在动态系统中进行的实验,在某些实验单元上的干预措施通过限制约束(例如有限的库存)影响其他单位。尽管具有实践意义,但这个“马尔可夫”干扰问题的最佳估计量在很大程度上是启发式性的,而且他们的偏见尚不很好地理解。我们在政策评估之一等实验中正式推论问题。与最先进的启发式方法相比,虽然公正的估计量显然受到了差异的巨大惩罚。我们介绍了一个上的估计器:Q(DQ)估计器中的差异。我们表明,DQ估计器通常可以比非政策评估的差异呈指数级的差异。同时,其偏见是干预措施的二阶。这产生了惊人的偏见变化权衡,因此DQ估计器有效地主导了最新的替代方案。从理论的角度来看,我们介绍了三种独立的新型技术,这些技术对强化理论(RL)具有独立感兴趣。我们的经验评估包括一组在城市级乘车模拟器上进行的实验。
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在线学习通常需要探索以最大程度地提高长期奖励,但这是以短期“遗憾”为代价的。我们研究如何在多个小组之间分担这种探索成本。例如,在临床试验环境中,分配了亚最佳治疗的患者有效地产生了勘探成本。当患者根据种族或年龄与自然群体相关联时,自然要问任何单一群体所承担的探索成本是否“公平”。如此有动力,我们介绍了“分组”的强盗模型。我们利用公理讨价还价的理论,尤其是纳什议价解决方案,以形式化可能构成跨群体勘探成本的公平分裂的方式。一方面,我们表明,任何遗憾的政策都引起了最不公平的结果:此类政策将在可能的情况下传递最“处于弱势”的群体。更具建设性的方式,我们得出了最佳公平且同时享受“公平价格”的政策。我们通过对华法林剂量的上下文匪徒进行案例研究来说明我们的算法框架的相对优点,我们关注多个种族和年龄段的探索成本。
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库存记录不正确,经常发生,某些措施的年销售额约为4%。手动检测库存不准确性的成本较高,现有算法解决方案几乎完全依赖于从纵向数据中学习,这在现代零售操作引起的动态环境中不足。取而代之的是,我们提出了基于商店和SKU上的横截面数据的解决方案,观察到检测库存不准确性可以被视为识别(低级别)泊松矩阵中异常的问题。在低级别矩阵中检测到的最先进的方法显然不足。具体而言,从理论的角度来看,这些方法的恢复保证要求需要观察到无反对的条目,而噪音消失了(在我们的问题中,在许多应用中都不是这种情况)。如此有动力,我们提出了一种在概念上简单的入门方法,以在低级别的泊松矩阵中进行异常检测。我们的方法适合一类概率异常模型。我们表明,我们的算法所产生的成本以最低最佳最佳速率接近最佳算法。使用来自消费品零售商的合成数据和真实数据,我们表明我们的方法可提供超过现有检测方法的10倍成本降低。在此过程中,我们建立了最新的工作,该工作寻求矩阵完成的入门错误保证,并为次指定矩阵确定此类保证,这是独立利益的结果。
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The number of international benchmarking competitions is steadily increasing in various fields of machine learning (ML) research and practice. So far, however, little is known about the common practice as well as bottlenecks faced by the community in tackling the research questions posed. To shed light on the status quo of algorithm development in the specific field of biomedical imaging analysis, we designed an international survey that was issued to all participants of challenges conducted in conjunction with the IEEE ISBI 2021 and MICCAI 2021 conferences (80 competitions in total). The survey covered participants' expertise and working environments, their chosen strategies, as well as algorithm characteristics. A median of 72% challenge participants took part in the survey. According to our results, knowledge exchange was the primary incentive (70%) for participation, while the reception of prize money played only a minor role (16%). While a median of 80 working hours was spent on method development, a large portion of participants stated that they did not have enough time for method development (32%). 25% perceived the infrastructure to be a bottleneck. Overall, 94% of all solutions were deep learning-based. Of these, 84% were based on standard architectures. 43% of the respondents reported that the data samples (e.g., images) were too large to be processed at once. This was most commonly addressed by patch-based training (69%), downsampling (37%), and solving 3D analysis tasks as a series of 2D tasks. K-fold cross-validation on the training set was performed by only 37% of the participants and only 50% of the participants performed ensembling based on multiple identical models (61%) or heterogeneous models (39%). 48% of the respondents applied postprocessing steps.
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Foveated imaging provides a better tradeoff between situational awareness (field of view) and resolution and is critical in long-wavelength infrared regimes because of the size, weight, power, and cost of thermal sensors. We demonstrate computational foveated imaging by exploiting the ability of a meta-optical frontend to discriminate between different polarization states and a computational backend to reconstruct the captured image/video. The frontend is a three-element optic: the first element which we call the "foveal" element is a metalens that focuses s-polarized light at a distance of $f_1$ without affecting the p-polarized light; the second element which we call the "perifoveal" element is another metalens that focuses p-polarized light at a distance of $f_2$ without affecting the s-polarized light. The third element is a freely rotating polarizer that dynamically changes the mixing ratios between the two polarization states. Both the foveal element (focal length = 150mm; diameter = 75mm), and the perifoveal element (focal length = 25mm; diameter = 25mm) were fabricated as polarization-sensitive, all-silicon, meta surfaces resulting in a large-aperture, 1:6 foveal expansion, thermal imaging capability. A computational backend then utilizes a deep image prior to separate the resultant multiplexed image or video into a foveated image consisting of a high-resolution center and a lower-resolution large field of view context. We build a first-of-its-kind prototype system and demonstrate 12 frames per second real-time, thermal, foveated image, and video capture in the wild.
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深度学习表明,最近在胸部X射线中对异常进行分类方面的成功,但是与自然图像数据集相比,数据集仍然很小。对异常本地化的监督已被证明可以改善训练有素的模型,部分补偿了数据集大小。但是,明确标记这些异常需要专家,并且非常耗时。我们提出了一种潜在的可扩展方法,用于使用眼动物跟踪器收集隐式定位数据,以捕获注视位置和麦克风来捕获报告的概念,从而模仿阅读室的设置。由五位放射科医生标记了所得的反射式(报告和眼睛跟踪数据,用于胸部X射线异常的定位)数据集,并包含3,032个同步的眼球跟踪数据集和时间戳报告的同步集,并从模拟的报告中进行了2,616胸部X射线的转录。 CXR数据集。我们还提供辅助注释,包括围绕肺和心脏的边界框以及由椭圆形成的椭圆形成异常和图像级标签的验证标签。此外,数据的一小部分包含所有放射科医生的读数,从而可以计算评估者分数。
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This paper presents a machine learning approach to multidimensional item response theory (MIRT), a class of latent factor models that can be used to model and predict student performance from observed assessment data. Inspired by collaborative filtering, we define a general class of models that includes many MIRT models. We discuss the use of penalized joint maximum likelihood (JML) to estimate individual models and cross-validation to select the best performing model. This model evaluation process can be optimized using batching techniques, such that even sparse large-scale data can be analyzed efficiently. We illustrate our approach with simulated and real data, including an example from a massive open online course (MOOC). The high-dimensional model fit to this large and sparse dataset does not lend itself well to traditional methods of factor interpretation. By analogy to recommender-system applications, we propose an alternative "validation" of the factor model, using auxiliary information about the popularity of items consulted during an open-book exam in the course.
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Real-world robotic grasping can be done robustly if a complete 3D Point Cloud Data (PCD) of an object is available. However, in practice, PCDs are often incomplete when objects are viewed from few and sparse viewpoints before the grasping action, leading to the generation of wrong or inaccurate grasp poses. We propose a novel grasping strategy, named 3DSGrasp, that predicts the missing geometry from the partial PCD to produce reliable grasp poses. Our proposed PCD completion network is a Transformer-based encoder-decoder network with an Offset-Attention layer. Our network is inherently invariant to the object pose and point's permutation, which generates PCDs that are geometrically consistent and completed properly. Experiments on a wide range of partial PCD show that 3DSGrasp outperforms the best state-of-the-art method on PCD completion tasks and largely improves the grasping success rate in real-world scenarios. The code and dataset will be made available upon acceptance.
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Optical coherence tomography (OCT) captures cross-sectional data and is used for the screening, monitoring, and treatment planning of retinal diseases. Technological developments to increase the speed of acquisition often results in systems with a narrower spectral bandwidth, and hence a lower axial resolution. Traditionally, image-processing-based techniques have been utilized to reconstruct subsampled OCT data and more recently, deep-learning-based methods have been explored. In this study, we simulate reduced axial scan (A-scan) resolution by Gaussian windowing in the spectral domain and investigate the use of a learning-based approach for image feature reconstruction. In anticipation of the reduced resolution that accompanies wide-field OCT systems, we build upon super-resolution techniques to explore methods to better aid clinicians in their decision-making to improve patient outcomes, by reconstructing lost features using a pixel-to-pixel approach with an altered super-resolution generative adversarial network (SRGAN) architecture.
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Using Structural Health Monitoring (SHM) systems with extensive sensing arrangements on every civil structure can be costly and impractical. Various concepts have been introduced to alleviate such difficulties, such as Population-based SHM (PBSHM). Nevertheless, the studies presented in the literature do not adequately address the challenge of accessing the information on different structural states (conditions) of dissimilar civil structures. The study herein introduces a novel framework named Structural State Translation (SST), which aims to estimate the response data of different civil structures based on the information obtained from a dissimilar structure. SST can be defined as Translating a state of one civil structure to another state after discovering and learning the domain-invariant representation in the source domains of a dissimilar civil structure. SST employs a Domain-Generalized Cycle-Generative (DGCG) model to learn the domain-invariant representation in the acceleration datasets obtained from a numeric bridge structure that is in two different structural conditions. In other words, the model is tested on three dissimilar numeric bridge models to translate their structural conditions. The evaluation results of SST via Mean Magnitude-Squared Coherence (MMSC) and modal identifiers showed that the translated bridge states (synthetic states) are significantly similar to the real ones. As such, the minimum and maximum average MMSC values of real and translated bridge states are 91.2% and 97.1%, the minimum and the maximum difference in natural frequencies are 5.71% and 0%, and the minimum and maximum Modal Assurance Criterion (MAC) values are 0.998 and 0.870. This study is critical for data scarcity and PBSHM, as it demonstrates that it is possible to obtain data from structures while the structure is actually in a different condition or state.
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