铁路是一个复杂的系统,包括多个基础设施和滚动库存资产。为了安全,可靠,有效地操作系统,需要监视许多组件的条件。为了自动化此过程,可以使用数据驱动的故障检测和诊断模型。但是,实际上,如果培训数据集并不代表所有可能的未来条件,则数据驱动模型的性能可能会受到损害。我们建议通过学习特征表示,一方面是对操作或环境因素不变的,但另一方面,对资产的健康状况的变化敏感。我们评估了如何在有监督的和无监督的故障检测和诊断任务上使用对比度学习,并在铁路系统中进行实际状态监控数据集 - 来自基础架构资产的一个图像数据集和来自滚动库存资产的一次时间序列数据集。首先,我们评估了标有标记图像数据集的铁路卧铺缺陷分类任务上有监督的对比功能学习的性能。其次,我们评估了无监督的对比功能学习的性能,而没有在铁路轮数据集的异常检测任务上访问故障样本。在这里,我们检验了特征编码器对降解的敏感性是否对数据中的新故障模式敏感的假设。我们的结果表明,与最先进的方法相比,对比功能学习可以提高有关卧铺的监督分类任务的绩效。此外,在有关铁路轮的异常检测任务上,与最新方法相比,炮击缺陷的检测得到了改善。
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由于培训和测试数据分布之间的域移动,新的操作条件可能会导致故障诊断模型的大量性能下降。尽管已经提出了几种域的适应方法来克服此类域移位,但如果两个域中表示的故障类别不相同,则其应用是有限的。为了在两个不同的域之间启用训练有素的模型的更好可传递性,尤其是在两个域之间仅共享健康数据类别的设置中,我们提出了一个新的框架,以基于生成不同的故障签名的部分和开放式域适应一个瓦斯林甘。提出的框架的主要贡献是具有两个主要不同特征的受控合成断层数据生成。首先,所提出的方法使目标域中仅能访问目标域中的健康样品和源域中的样本错误,从而在目标域中生成未观察到的故障类型。其次,可以将故障产生控制以精确生成不同的故障类型和故障严重程度。所提出的方法特别适合于极端域的适应设置,这些设置在复杂和安全关键系统的背景下特别相关,其中两个域之间仅共享一个类。我们在两个轴承断层诊断案例研究上评估了部分和开放式域适应任务的拟议框架。我们在不同标签空间设置中进行的实验展示了提出的框架的多功能性。与给定较大域间隙的其他方法相比,提出的方法提供了优越的结果。
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Robots need to be able to adapt to unexpected changes in the environment such that they can autonomously succeed in their tasks. However, hand-designing feedback models for adaptation is tedious, if at all possible, making data-driven methods a promising alternative. In this paper we introduce a full framework for learning feedback models for reactive motion planning. Our pipeline starts by segmenting demonstrations of a complete task into motion primitives via a semi-automated segmentation algorithm. Then, given additional demonstrations of successful adaptation behaviors, we learn initial feedback models through learning from demonstrations. In the final phase, a sample-efficient reinforcement learning algorithm fine-tunes these feedback models for novel task settings through few real system interactions. We evaluate our approach on a real anthropomorphic robot in learning a tactile feedback task.
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The release of ChatGPT, a language model capable of generating text that appears human-like and authentic, has gained significant attention beyond the research community. We expect that the convincing performance of ChatGPT incentivizes users to apply it to a variety of downstream tasks, including prompting the model to simplify their own medical reports. To investigate this phenomenon, we conducted an exploratory case study. In a questionnaire, we asked 15 radiologists to assess the quality of radiology reports simplified by ChatGPT. Most radiologists agreed that the simplified reports were factually correct, complete, and not potentially harmful to the patient. Nevertheless, instances of incorrect statements, missed key medical findings, and potentially harmful passages were reported. While further studies are needed, the initial insights of this study indicate a great potential in using large language models like ChatGPT to improve patient-centered care in radiology and other medical domains.
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Local patterns play an important role in statistical physics as well as in image processing. Two-dimensional ordinal patterns were studied by Ribeiro et al. who determined permutation entropy and complexity in order to classify paintings and images of liquid crystals. Here we find that the 2 by 2 patterns of neighboring pixels come in three types. The statistics of these types, expressed by two parameters, contains the relevant information to describe and distinguish textures. The parameters are most stable and informative for isotropic structures.
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Many dialogue systems (DSs) lack characteristics humans have, such as emotion perception, factuality, and informativeness. Enhancing DSs with knowledge alleviates this problem, but, as many ways of doing so exist, keeping track of all proposed methods is difficult. Here, we present the first survey of knowledge-enhanced DSs. We define three categories of systems - internal, external, and hybrid - based on the knowledge they use. We survey the motivation for enhancing DSs with knowledge, used datasets, and methods for knowledge search, knowledge encoding, and knowledge incorporation. Finally, we propose how to improve existing systems based on theories from linguistics and cognitive science.
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Attention-based multiple instance learning (AMIL) algorithms have proven to be successful in utilizing gigapixel whole-slide images (WSIs) for a variety of different computational pathology tasks such as outcome prediction and cancer subtyping problems. We extended an AMIL approach to the task of survival prediction by utilizing the classical Cox partial likelihood as a loss function, converting the AMIL model into a nonlinear proportional hazards model. We applied the model to tissue microarray (TMA) slides of 330 lung cancer patients. The results show that AMIL approaches can handle very small amounts of tissue from a TMA and reach similar C-index performance compared to established survival prediction methods trained with highly discriminative clinical factors such as age, cancer grade, and cancer stage
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Nucleolar organizer regions (NORs) are parts of the DNA that are involved in RNA transcription. Due to the silver affinity of associated proteins, argyrophilic NORs (AgNORs) can be visualized using silver-based staining. The average number of AgNORs per nucleus has been shown to be a prognostic factor for predicting the outcome of many tumors. Since manual detection of AgNORs is laborious, automation is of high interest. We present a deep learning-based pipeline for automatically determining the AgNOR-score from histopathological sections. An additional annotation experiment was conducted with six pathologists to provide an independent performance evaluation of our approach. Across all raters and images, we found a mean squared error of 0.054 between the AgNOR- scores of the experts and those of the model, indicating that our approach offers performance comparable to humans.
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Mitotic activity is key for the assessment of malignancy in many tumors. Moreover, it has been demonstrated that the proportion of abnormal mitosis to normal mitosis is of prognostic significance. Atypical mitotic figures (MF) can be identified morphologically as having segregation abnormalities of the chromatids. In this work, we perform, for the first time, automatic subtyping of mitotic figures into normal and atypical categories according to characteristic morphological appearances of the different phases of mitosis. Using the publicly available MIDOG21 and TUPAC16 breast cancer mitosis datasets, two experts blindly subtyped mitotic figures into five morphological categories. Further, we set up a state-of-the-art object detection pipeline extending the anchor-free FCOS approach with a gated hierarchical subclassification branch. Our labeling experiment indicated that subtyping of mitotic figures is a challenging task and prone to inter-rater disagreement, which we found in 24.89% of MF. Using the more diverse MIDOG21 dataset for training and TUPAC16 for testing, we reached a mean overall average precision score of 0.552, a ROC AUC score of 0.833 for atypical/normal MF and a mean class-averaged ROC-AUC score of 0.977 for discriminating the different phases of cells undergoing mitosis.
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Modern machine learning models are often constructed taking into account multiple objectives, e.g., to minimize inference time while also maximizing accuracy. Multi-objective hyperparameter optimization (MHPO) algorithms return such candidate models and the approximation of the Pareto front is used to assess their performance. However, when estimating generalization performance of an approximation of a Pareto front found on a validation set by computing the performance of the individual models on the test set, models might no longer be Pareto-optimal. This makes it unclear how to measure performance. To resolve this, we provide a novel evaluation protocol that allows measuring the generalization performance of MHPO methods and to study its capabilities for comparing two optimization experiments.
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