深度学习算法的最新进展为解决许多医学图像分析问题带来了重大好处。培训深度学习模型通常需要具有专家标记注释的大型数据集。但是,获取专家标记的注释不仅昂贵,而且主观,容易出错,并且观察者内部变异性会引入标签。由于解剖学的模棱两可,使用深度学习模型来细分医学图像时,这尤其是一个问题。基于图像的医学诊断工具使用经过不正确分段标签训练的深度学习模型可以导致错误的诊断和治疗建议。与单评论注释相比,多评价者注释可能更适合于使用小型培训集的深度学习模型进行训练。本文的目的是开发和评估一种基于MRI中病变特征的多评价者注释和解剖学知识来生成概率标签的方法,以及一种使用概率的标签使用归一化活动性损失作为A的病变特征的解剖学知识,以训练分割模型”。耐噪声损失的功能。通过将17个膝盖MRI扫描的二进制基础真理进行比较,以评估该模型,以用于临床分割和检测骨髓病变(BML)。该方法与二进制跨透镜损失函数相比,该方法成功提高了精度14,召回22和骰子得分8%。总体而言,这项工作的结果表明,使用软标签的拟议归一化主动损失成功地减轻了嘈杂标签的影响。
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提出了一种算法,用于构建与计算机断层扫描成像的两相材料构建高阶签名距离场。符号距离字段是高阶的,因为它没有与采样信号的距离变换相关联的量化伪像。使用最接近的点算法来解决窄带,该算法扩展到不是符号距离字段的隐式嵌入式。高阶快速扫描算法用于将窄带扩展到域的其余部分。在理想的隐式表面上验证了窄带和扩展方法的准确性顺序。该方法适用于10个精馏牛小梁骨的切除立方体。用这些受试者验证表面,相密度估计和局部形态学的定位。由于嵌入是高阶,梯度,因此可以在图像数据中本地局部地精确地估计曲线。
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Deep Reinforcement Learning (RL) agents are susceptible to adversarial noise in their observations that can mislead their policies and decrease their performance. However, an adversary may be interested not only in decreasing the reward, but also in modifying specific temporal logic properties of the policy. This paper presents a metric that measures the exact impact of adversarial attacks against such properties. We use this metric to craft optimal adversarial attacks. Furthermore, we introduce a model checking method that allows us to verify the robustness of RL policies against adversarial attacks. Our empirical analysis confirms (1) the quality of our metric to craft adversarial attacks against temporal logic properties, and (2) that we are able to concisely assess a system's robustness against attacks.
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马尔可夫决策过程(MDP)是在顺序决策中常用的正式模型。 MDP捕获了可能出现的随机性,例如,通过过渡函数中的概率从不精确的执行器中捕获。但是,在数据驱动的应用程序中,从(有限)数据中得出精确的概率引入了可能导致意外或不良结果的统计错误。不确定的MDP(UMDP)不需要精确的概率,而是在过渡中使用所谓的不确定性集,占此类有限的数据。正式验证社区中的工具有效地计算了强大的政策,这些政策在不确定性集中最坏的情况下,可以证明遵守正式规格,例如安全限制。我们不断地以强大的学习方法与将专用的贝叶斯推理方案与强大策略的计算结合在一起的任何时间学习方法中不断学习MDP的过渡概率。特别是,我们的方法(1)将概率近似为间隔,(2)适应可能与中间模型不一致的新数据,并且可以随时停止(3),以在UMDP上计算强大的策略,以忠实地捕获稳健的策略到目前为止的数据。我们展示了我们的方法的有效性,并将其与在几个基准的实验评估中对UMDP计算出的UMDP进行了比较。
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从显微镜图像体积分段3D细胞核对于生物学和临床分析至关重要,从而实现了细胞表达模式和细胞谱系的研究。然而,神经元核的当前数据集通常包含小于$ 10 ^ {\ text {-} 3} \ mm ^ 3 $的卷,每卷少于500美元,无法揭示大脑区域的复杂性并限制神经元的调查结构。在本文中,我们推动了向子立方毫米秤的任务向前推进了,并用两个完全注释的卷策划了NUCMM数据集:1美元\ mm ^ $电子显微镜(EM)含有几乎整个斑马鱼大脑,大约170,000左右核;还有0.25美元\ mm ^ 3 $ micro-ct(uct)卷,其中鼠标视觉皮层的一部分,大约7,000个核。具有两种成像模态,体积大小和实例数量显着增加,我们在外观和密度中发现了神经元核的大量多样性,对该领域引入了新的挑战。我们还进行统计分析以定量地说明这些挑战。为了解决挑战,我们提出了一种新颖的混合表示学习模型,该模型结合了前景掩模,轮廓图和签名距离变换来生产高质量的3D面罩。 NUCMM数据集上的基准比较表明,我们所提出的方法显着优于最先进的核细胞分割方法。代码和数据可在https://connectomics-bazaar.github.io/proj/nucmm/index.html中获得。
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In this paper, we propose a novel technique, namely INVALIDATOR, to automatically assess the correctness of APR-generated patches via semantic and syntactic reasoning. INVALIDATOR reasons about program semantic via program invariants while it also captures program syntax via language semantic learned from large code corpus using the pre-trained language model. Given a buggy program and the developer-patched program, INVALIDATOR infers likely invariants on both programs. Then, INVALIDATOR determines that a APR-generated patch overfits if: (1) it violates correct specifications or (2) maintains errors behaviors of the original buggy program. In case our approach fails to determine an overfitting patch based on invariants, INVALIDATOR utilizes a trained model from labeled patches to assess patch correctness based on program syntax. The benefit of INVALIDATOR is three-fold. First, INVALIDATOR is able to leverage both semantic and syntactic reasoning to enhance its discriminant capability. Second, INVALIDATOR does not require new test cases to be generated but instead only relies on the current test suite and uses invariant inference to generalize the behaviors of a program. Third, INVALIDATOR is fully automated. We have conducted our experiments on a dataset of 885 patches generated on real-world programs in Defects4J. Experiment results show that INVALIDATOR correctly classified 79% overfitting patches, accounting for 23% more overfitting patches being detected by the best baseline. INVALIDATOR also substantially outperforms the best baselines by 14% and 19% in terms of Accuracy and F-Measure, respectively.
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When robots learn reward functions using high capacity models that take raw state directly as input, they need to both learn a representation for what matters in the task -- the task ``features" -- as well as how to combine these features into a single objective. If they try to do both at once from input designed to teach the full reward function, it is easy to end up with a representation that contains spurious correlations in the data, which fails to generalize to new settings. Instead, our ultimate goal is to enable robots to identify and isolate the causal features that people actually care about and use when they represent states and behavior. Our idea is that we can tune into this representation by asking users what behaviors they consider similar: behaviors will be similar if the features that matter are similar, even if low-level behavior is different; conversely, behaviors will be different if even one of the features that matter differs. This, in turn, is what enables the robot to disambiguate between what needs to go into the representation versus what is spurious, as well as what aspects of behavior can be compressed together versus not. The notion of learning representations based on similarity has a nice parallel in contrastive learning, a self-supervised representation learning technique that maps visually similar data points to similar embeddings, where similarity is defined by a designer through data augmentation heuristics. By contrast, in order to learn the representations that people use, so we can learn their preferences and objectives, we use their definition of similarity. In simulation as well as in a user study, we show that learning through such similarity queries leads to representations that, while far from perfect, are indeed more generalizable than self-supervised and task-input alternatives.
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The latent space of autoencoders has been improved for clustering image data by jointly learning a t-distributed embedding with a clustering algorithm inspired by the neighborhood embedding concept proposed for data visualization. However, multivariate tabular data pose different challenges in representation learning than image data, where traditional machine learning is often superior to deep tabular data learning. In this paper, we address the challenges of learning tabular data in contrast to image data and present a novel Gaussian Cluster Embedding in Autoencoder Latent Space (G-CEALS) algorithm by replacing t-distributions with multivariate Gaussian clusters. Unlike current methods, the proposed approach independently defines the Gaussian embedding and the target cluster distribution to accommodate any clustering algorithm in representation learning. A trained G-CEALS model extracts a quality embedding for unseen test data. Based on the embedding clustering accuracy, the average rank of the proposed G-CEALS method is 1.4 (0.7), which is superior to all eight baseline clustering and cluster embedding methods on seven tabular data sets. This paper shows one of the first algorithms to jointly learn embedding and clustering to improve multivariate tabular data representation in downstream clustering.
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An unbiased scene graph generation (SGG) algorithm referred to as Skew Class-balanced Re-weighting (SCR) is proposed for considering the unbiased predicate prediction caused by the long-tailed distribution. The prior works focus mainly on alleviating the deteriorating performances of the minority predicate predictions, showing drastic dropping recall scores, i.e., losing the majority predicate performances. It has not yet correctly analyzed the trade-off between majority and minority predicate performances in the limited SGG datasets. In this paper, to alleviate the issue, the Skew Class-balanced Re-weighting (SCR) loss function is considered for the unbiased SGG models. Leveraged by the skewness of biased predicate predictions, the SCR estimates the target predicate weight coefficient and then re-weights more to the biased predicates for better trading-off between the majority predicates and the minority ones. Extensive experiments conducted on the standard Visual Genome dataset and Open Image V4 \& V6 show the performances and generality of the SCR with the traditional SGG models.
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In this paper we discuss the theory used in the design of an open source lightmorphic signatures analysis toolkit (LSAT). In addition to providing a core functionality, the software package enables specific optimizations with its modular and customizable design. To promote its usage and inspire future contributions, LSAT is publicly available. By using a self-supervised neural network and augmented machine learning algorithms, LSAT provides an easy-to-use interface with ample documentation. The experiments demonstrate that LSAT improves the otherwise tedious and error-prone tasks of translating lightmorphic associated data into usable spectrograms, enhanced with parameter tuning and performance analysis. With the provided mathematical functions, LSAT validates the nonlinearity encountered in the data conversion process while ensuring suitability of the forecasting algorithms.
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