病理学家对患病组织的视觉微观研究一直是一个多世纪以来癌症诊断和预后的基石。最近,深度学习方法在组织图像的分析和分类方面取得了重大进步。但是,关于此类模型在生成组织病理学图像的实用性方面的工作有限。这些合成图像在病理学中有多种应用,包括教育,熟练程度测试,隐私和数据共享的公用事业。最近,引入了扩散概率模型以生成高质量的图像。在这里,我们首次研究了此类模型的潜在用途以及优先的形态加权和颜色归一化,以合成脑癌的高质量组织病理学图像。我们的详细结果表明,与生成对抗网络相比,扩散概率模型能够合成各种组织病理学图像,并且具有较高的性能。
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During training, reinforcement learning systems interact with the world without considering the safety of their actions. When deployed into the real world, such systems can be dangerous and cause harm to their surroundings. Often, dangerous situations can be mitigated by defining a set of rules that the system should not violate under any conditions. For example, in robot navigation, one safety rule would be to avoid colliding with surrounding objects and people. In this work, we define safety rules in terms of the relationships between the agent and objects and use them to prevent reinforcement learning systems from performing potentially harmful actions. We propose a new safe epsilon-greedy algorithm that uses safety rules to override agents' actions if they are considered to be unsafe. In our experiments, we show that a safe epsilon-greedy policy significantly increases the safety of the agent during training, improves the learning efficiency resulting in much faster convergence, and achieves better performance than the base model.
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Various methods using machine and deep learning have been proposed to tackle different tasks in predictive process monitoring, forecasting for an ongoing case e.g. the most likely next event or suffix, its remaining time, or an outcome-related variable. Recurrent neural networks (RNNs), and more specifically long short-term memory nets (LSTMs), stand out in terms of popularity. In this work, we investigate the capabilities of such an LSTM to actually learn the underlying process model structure of an event log. We introduce an evaluation framework that combines variant-based resampling and custom metrics for fitness, precision and generalization. We evaluate 4 hypotheses concerning the learning capabilities of LSTMs, the effect of overfitting countermeasures, the level of incompleteness in the training set and the level of parallelism in the underlying process model. We confirm that LSTMs can struggle to learn process model structure, even with simplistic process data and in a very lenient setup. Taking the correct anti-overfitting measures can alleviate the problem. However, these measures did not present themselves to be optimal when selecting hyperparameters purely on predicting accuracy. We also found that decreasing the amount of information seen by the LSTM during training, causes a sharp drop in generalization and precision scores. In our experiments, we could not identify a relationship between the extent of parallelism in the model and the generalization capability, but they do indicate that the process' complexity might have impact.
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The underlying dynamics and patterns of 3D surface meshes deforming over time can be discovered by unsupervised learning, especially autoencoders, which calculate low-dimensional embeddings of the surfaces. To study the deformation patterns of unseen shapes by transfer learning, we want to train an autoencoder that can analyze new surface meshes without training a new network. Here, most state-of-the-art autoencoders cannot handle meshes of different connectivity and therefore have limited to no generalization capacities to new meshes. Also, reconstruction errors strongly increase in comparison to the errors for the training shapes. To address this, we propose a novel spectral CoSMA (Convolutional Semi-Regular Mesh Autoencoder) network. This patch-based approach is combined with a surface-aware training. It reconstructs surfaces not presented during training and generalizes the deformation behavior of the surfaces' patches. The novel approach reconstructs unseen meshes from different datasets in superior quality compared to state-of-the-art autoencoders that have been trained on these shapes. Our transfer learning errors on unseen shapes are 40% lower than those from models learned directly on the data. Furthermore, baseline autoencoders detect deformation patterns of unseen mesh sequences only for the whole shape. In contrast, due to the employed regional patches and stable reconstruction quality, we can localize where on the surfaces these deformation patterns manifest.
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在过去几十年中,功能选择吸引了很多关注,因为它可以降低数据维度,同时保持功能的原始物理含义,这比功能提取可以更好地解释性。但是,大多数现有的功能选择方法,尤其是基于深度学习的方法,通常集中在仅具有很高分数的功能上,但忽略了那些在训练过程中得分较低的人以及重要的候选功能的顺序。这可能是有风险的,因为不幸的是,在培训过程中可能会忽略一些重要和相关的功能,从而导致次优的解决方案或误导性选择。在我们的工作中,我们通过利用较少重要性分数的功能来处理功能选择,并根据新颖的互补功能掩码提出功能选择框架。我们的方法是通用的,可以轻松地集成到现有的基于深度学习的特征选择方法中,以提高其性能。实验是在基准数据集上进行的,并表明所提出的方法可以选择比艺术状态更具代表性和信息性的特征。
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全球越来越多的大学将各种形式的在线学习和混合学习作为其学术课程的一部分。此外,由于199年大流行而造成的最新变化导致在线教育的重要性和无处不在。电子学习的主要优点之一不仅是改善学生的学习经验并扩大教育前景,而且还可以通过学习分析来洞悉学生的学习过程。这项研究有助于通过以下方式改善和理解电子学习过程的主题。首先,我们证明可以根据从学生的行为数据中得出的顺序模式来构建准确的预测模型,这些模式能够在课程的早期识别出表现不佳的学生。其次,我们通过研究是否应根据特定于课程的顺序模式或基于更一般的行为模式的几个课程来构建每个课程的预测模型,从而调查了建立此类预测模型的特异性征用性权衡。最后,我们提出了一种捕获行为数据中时间方面的方法,并分析了其对模型预测性能的影响。我们改进的序列分类技术的结果能够以高度准确性来预测学生的表现,而对于课程特异性模型的结果达到了90%。
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人工智能(AI),机器学习和深度学习(DL)方法在生物医学图像分析领域变得越来越重要。但是,为了利用此类方法的全部潜力,需要作为训练数据代表数量的实验获得的图像,其中包含大量手动注释对象。在这里,我们将语法(合成数据)介绍为一种新的方法,用于生成合成,光现实和高度复杂的生物医学图像作为DL系统的训练数据。我们在组织学切片中的肌肉纤维和结缔组织分析的背景下显示了方法的多功能性。我们证明,可以在以前看不见的现实世界数据上执行强大和专家级的细分任务,而无需仅使用合成训练数据进行手动注释。作为一种完全参数技术,我们的方法为生成对抗网络(GAN)构成了可解释的可控替代方案,并且有可能在显微镜及其他地区的各种生物医学应用中显着加速定量图像分析。
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当前的AI系统旨在解决近世界问题的假设,即基础世界或多或少是相同的。但是,当处理现实世界问题时,这些假设可能无效,因为可能会发生突然和意外的变化。为了有效地在现实世界中部署AI驱动的系统,AI系统应该能够快速处理开放世界的新颖性。不可避免地,处理开放世界的新颖性引发了一个重要的新颖性困难问题。知道一种新颖性是否比另一种新颖性更难处理,可以帮助研究人员系统地训练他们的系统。此外,它还可以用作对新颖性AI系统的性能的测量。在本文中,我们建议将新颖性的难度定义为在引入新颖性后执行已知任务的相对困难。我们提出了一种通用方法,可用于近似难度。我们介绍了使用我们的方法的难度的近似值,并显示了它如何与旨在处理新颖性的AI剂的评估结果保持一致。
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生物视觉系统在没有监督的情况下学习视觉表示的能力是无与伦比的。在机器学习中,对比度学习(CL)已导致以无监督的方式形成对象表示。这些系统学习了对图像的增强操作不变的表示,例如裁剪或翻转。相反,生物视觉系统利用视觉体验的时间结构。这可以访问CL中常用的不常见的增强,例如从多个观点或不同背景观看相同的对象。在这里,我们系统地研究并比较了此类基于时间的增强对对象类别的潜在好处。我们的结果表明,基于时间的增强功能超过了最先进的图像增强功能。具体而言,我们的分析表明:1)3-D对象旋转极大地改善了对象类别的学习; 2)在不断变化的背景下查看对象对于学习丢弃与背景相关的信息至关重要。总体而言,我们得出的结论是,基于时间的增强可以极大地改善对比度学习,从而缩小人工和生物视觉系统之间的差距。
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绝对位置精度是室内定位系统(ILS)的关键性能标准。由于IL是异质且复杂的网络物理系统,因此本地化精度取决于环境,系统配置和应用程序过程的各种影响。为了确定系统的位置准确性,必须考虑这些因素。我们提出了一种策略,用于分析使用决策树与应用程序相关或与技术相关的分类组合的IL对位置准确性的影响。使用来自120个实验的经验数据对拟议的策略进行了验证。考虑到自主移动机器人在仓库中的应用,在不同的应用驱动的影响因素下确定了超宽带和基于激光雷达的IL的准确性。最后,介绍了分析决策树以比较系统性能,找到合适的系统,优化环境或系统配置并了解不同影响因素的相关性的机会和局限性。
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