合成孔径雷达(SAR)数据中的异常值(异常值)的存在以及统计图像模型中的错误指定可能导致推断不准确。为了避免此类问题,提出了基于强大的估计过程的瑞利回归模型,作为模拟此类数据的更现实的方法。本文旨在获得瑞利回归模型参数估计量与异常值的存在。提出的方法考虑了加权最大似然法,并使用模拟和测量的SAR图像提交了数值实验。使用蒙特卡洛模拟来评估有限信号长度中提出的可靠估计器性能,对离群值的敏感性和分解点。例如,非稳定估计器显示相对偏置值$ 65 $ - 折叠比损坏信号中强大方法提供的结果大。在灵敏度分析和分解点方面,强大的方案在两种措施的平均绝对值中分别降低了约96美元\%$和$ 10 \%$,以同情非稳定估计器。此外,使用两个SAR数据集比较了所提出的强稳定方案的地面类型和异常检测结果与文献中的竞争方法。
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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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Three main points: 1. Data Science (DS) will be increasingly important to heliophysics; 2. Methods of heliophysics science discovery will continually evolve, requiring the use of learning technologies [e.g., machine learning (ML)] that are applied rigorously and that are capable of supporting discovery; and 3. To grow with the pace of data, technology, and workforce changes, heliophysics requires a new approach to the representation of knowledge.
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In the Earth's magnetosphere, there are fewer than a dozen dedicated probes beyond low-Earth orbit making in-situ observations at any given time. As a result, we poorly understand its global structure and evolution, the mechanisms of its main activity processes, magnetic storms, and substorms. New Artificial Intelligence (AI) methods, including machine learning, data mining, and data assimilation, as well as new AI-enabled missions will need to be developed to meet this Sparse Data challenge.
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Temporal Graph Neural Network (TGNN) has been receiving a lot of attention recently due to its capability in modeling time-evolving graph-related tasks. Similar to Graph Neural Networks, it is also non-trivial to interpret predictions made by a TGNN due to its black-box nature. A major approach tackling this problems in GNNs is by analyzing the model' responses on some perturbations of the model's inputs, called perturbation-based explanation methods. While these methods are convenient and flexible since they do not need internal access to the model, does this lack of internal access prevent them from revealing some important information of the predictions? Motivated by that question, this work studies the limit of some classes of perturbation-based explanation methods. Particularly, by constructing some specific instances of TGNNs, we show (i) node-perturbation cannot reliably identify the paths carrying out the prediction, (ii) edge-perturbation is not reliable in determining all nodes contributing to the prediction and (iii) perturbing both nodes and edges does not reliably help us identify the graph's components carrying out the temporal aggregation in TGNNs.
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Despite the huge advancement in knowledge discovery and data mining techniques, the X-ray diffraction (XRD) analysis process has mostly remained untouched and still involves manual investigation, comparison, and verification. Due to the large volume of XRD samples from high-throughput XRD experiments, it has become impossible for domain scientists to process them manually. Recently, they have started leveraging standard clustering techniques, to reduce the XRD pattern representations requiring manual efforts for labeling and verification. Nevertheless, these standard clustering techniques do not handle problem-specific aspects such as peak shifting, adjacent peaks, background noise, and mixed phases; hence, resulting in incorrect composition-phase diagrams that complicate further steps. Here, we leverage data mining techniques along with domain expertise to handle these issues. In this paper, we introduce an incremental phase mapping approach based on binary peak representations using a new threshold based fuzzy dissimilarity measure. The proposed approach first applies an incremental phase computation algorithm on discrete binary peak representation of XRD samples, followed by hierarchical clustering or manual merging of similar pure phases to obtain the final composition-phase diagram. We evaluate our method on the composition space of two ternary alloy systems- Co-Ni-Ta and Co-Ti-Ta. Our results are verified by domain scientists and closely resembles the manually computed ground-truth composition-phase diagrams. The proposed approach takes us closer towards achieving the goal of complete end-to-end automated XRD analysis.
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Many studies have examined the shortcomings of word error rate (WER) as an evaluation metric for automatic speech recognition (ASR) systems, particularly when used for spoken language understanding tasks such as intent recognition and dialogue systems. In this paper, we propose Hybrid-SD (H_SD), a new hybrid evaluation metric for ASR systems that takes into account both semantic correctness and error rate. To generate sentence dissimilarity scores (SD), we built a fast and lightweight SNanoBERT model using distillation techniques. Our experiments show that the SNanoBERT model is 25.9x smaller and 38.8x faster than SRoBERTa while achieving comparable results on well-known benchmarks. Hence, making it suitable for deploying with ASR models on edge devices. We also show that H_SD correlates more strongly with downstream tasks such as intent recognition and named-entity recognition (NER).
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相干显微镜技术提供了跨科学和技术领域的材料的无与伦比的多尺度视图,从结构材料到量子设备,从综合电路到生物细胞。在构造更明亮的来源和高速探测器的驱动下,连贯的X射线显微镜方法(如Ptychography)有望彻底改变纳米级材料的特征。但是,相关的数据和计算需求显着增加意味着,常规方法不再足以从高速相干成像实验实时恢复样品图像。在这里,我们演示了一个工作流程,该工作流利用边缘的人工智能和高性能计算,以实现直接从检测器直接从检测器流出的X射线ptychography数据实时反演。拟议的AI支持的工作流程消除了传统的Ptychography施加的采样约束,从而使用比传统方法所需的数据较少的数据级允许低剂量成像。
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在过去的几年中,已经引入了许多基于输入数据扰动的解释方法,以提高我们对黑盒模型做出的决策的理解。这项工作的目的是引入一种新颖的扰动方案,以便可以获得更忠实和强大的解释。我们的研究重点是扰动方向对数据拓扑的影响。我们表明,在对离散的Gromov-Hausdorff距离的最坏情况分析以及通过持久的同源性的平均分析中,沿输入歧管的正交方向的扰动更好地保留了数据拓扑。从这些结果中,我们引入EMAP算法,实现正交扰动方案。我们的实验表明,EMAP不仅改善了解释者的性能,而且还可以帮助他们克服最近对基于扰动的方法的攻击。
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尽管最近关于了解深神经网络(DNN)的研究,但关于DNN如何产生其预测的问题仍然存在许多问题。特别是,给定对不同输入样本的类似预测,基本机制是否会产生这些预测?在这项工作中,我们提出了Neucept,这是一种局部发现关键神经元的方法,该神经元在模型的预测中起着重要作用,并确定模型的机制在产生这些预测中。我们首先提出一个关键的神经元识别问题,以最大程度地提高相互信息目标的序列,并提供一个理论框架,以有效地解决关键神经元,同时控制精度。Neucept接下来以无监督的方式学习了不同模型的机制。我们的实验结果表明,Neucept鉴定的神经元不仅对模型的预测具有强大的影响,而且还具有有关模型机制的有意义的信息。
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