财产数据的可用性是化学过程开发中的主要瓶颈之一,通常需要耗时且昂贵的实验或将设计空间限制为少数已知分子。这种瓶颈一直是预测性财产模型持续发展的动机。对于新分子的性质预测,群体贡献方法一直在开创性。最近,机器学习加入了更具成熟的财产预测模型。但是,即使取得了最近的成功,将物理约束集成到机器学习模型中仍然具有挑战性。物理约束对于许多热力学特性,例如吉布斯 - 杜纳姆(Gibbs-Dunham)关系至关重要,它将额外的复杂性层引入预测中。在这里,我们介绍了SPT-NRTL,这是一种机器学习模型,以预测热力学一致的活动系数并提供NRTL参数,以便于过程模拟。结果表明,SPT-NRTL在所有官能团的活性系数预测中的精度高于UNIFAC,并且能够以几乎实验的精度预测许多蒸气 - 液位均衡性,如示例性混合物所示。 N-己烷。为了简化SPT-NRTL的应用,用SPT-NRTL计算了100 000 000的NRTL参数,并在线提供。
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对混合物相位平衡的知识在性质和技术化学本质上至关重要。混合物的相位平衡计算需要活性系数。但是,由于实验成本高,有关活性系数的实验数据通常受到限制。为了准确有效地预测活性系数,最近已经开发了机器学习方法。然而,对于未知分子的活性系数,当前的机器学习方法仍然很差。在这项工作中,我们介绍了一个自然语言处理网络的微笑到properties-Transformer(SPT),以预测微笑代码的二进制限制活动系数。为了克服可用实验数据的局限性,我们最初是在从COSMO-RS(1000万个数据点)采样的大型合成数据数据集上训练我们的网络,然后对实验数据(20 870个数据点)进行微调。该训练策略使SPT能够准确预测限制活动系数,即使对于未知分子,与最新的活动系数预测(例如COSMO-RS,UNIFAC)相比,将平均预测误差一半切成一半,并改善了最近的机器学习方法。
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Machine learning models are typically evaluated by computing similarity with reference annotations and trained by maximizing similarity with such. Especially in the bio-medical domain, annotations are subjective and suffer from low inter- and intra-rater reliability. Since annotations only reflect the annotation entity's interpretation of the real world, this can lead to sub-optimal predictions even though the model achieves high similarity scores. Here, the theoretical concept of Peak Ground Truth (PGT) is introduced. PGT marks the point beyond which an increase in similarity with the reference annotation stops translating to better Real World Model Performance (RWMP). Additionally, a quantitative technique to approximate PGT by computing inter- and intra-rater reliability is proposed. Finally, three categories of PGT-aware strategies to evaluate and improve model performance are reviewed.
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Accurate PhotoVoltaic (PV) power generation forecasting is vital for the efficient operation of Smart Grids. The automated design of such accurate forecasting models for individual PV plants includes two challenges: First, information about the PV mounting configuration (i.e. inclination and azimuth angles) is often missing. Second, for new PV plants, the amount of historical data available to train a forecasting model is limited (cold-start problem). We address these two challenges by proposing a new method for day-ahead PV power generation forecasts called AutoPV. AutoPV is a weighted ensemble of forecasting models that represent different PV mounting configurations. This representation is achieved by pre-training each forecasting model on a separate PV plant and by scaling the model's output with the peak power rating of the corresponding PV plant. To tackle the cold-start problem, we initially weight each forecasting model in the ensemble equally. To tackle the problem of missing information about the PV mounting configuration, we use new data that become available during operation to adapt the ensemble weights to minimize the forecasting error. AutoPV is advantageous as the unknown PV mounting configuration is implicitly reflected in the ensemble weights, and only the PV plant's peak power rating is required to re-scale the ensemble's output. AutoPV also allows to represent PV plants with panels distributed on different roofs with varying alignments, as these mounting configurations can be reflected proportionally in the weighting. Additionally, the required computing memory is decoupled when scaling AutoPV to hundreds of PV plants, which is beneficial in Smart Grids with limited computing capabilities. For a real-world data set with 11 PV plants, the accuracy of AutoPV is comparable to a model trained on two years of data and outperforms an incrementally trained model.
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Decades of progress in simulation-based surrogate-assisted optimization and unprecedented growth in computational power have enabled researchers and practitioners to optimize previously intractable complex engineering problems. This paper investigates the possible benefit of a concurrent utilization of multiple simulation-based surrogate models to solve complex discrete optimization problems. To fulfill this, the so-called Self-Adaptive Multi-surrogate Assisted Efficient Global Optimization algorithm (SAMA-DiEGO), which features a two-stage online model management strategy, is proposed and further benchmarked on fifteen binary-encoded combinatorial and fifteen ordinal problems against several state-of-the-art non-surrogate or single surrogate assisted optimization algorithms. Our findings indicate that SAMA-DiEGO can rapidly converge to better solutions on a majority of the test problems, which shows the feasibility and advantage of using multiple surrogate models in optimizing discrete problems.
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Quantifying the perceptual similarity of two images is a long-standing problem in low-level computer vision. The natural image domain commonly relies on supervised learning, e.g., a pre-trained VGG, to obtain a latent representation. However, due to domain shift, pre-trained models from the natural image domain might not apply to other image domains, such as medical imaging. Notably, in medical imaging, evaluating the perceptual similarity is exclusively performed by specialists trained extensively in diverse medical fields. Thus, medical imaging remains devoid of task-specific, objective perceptual measures. This work answers the question: Is it necessary to rely on supervised learning to obtain an effective representation that could measure perceptual similarity, or is self-supervision sufficient? To understand whether recent contrastive self-supervised representation (CSR) may come to the rescue, we start with natural images and systematically evaluate CSR as a metric across numerous contemporary architectures and tasks and compare them with existing methods. We find that in the natural image domain, CSR behaves on par with the supervised one on several perceptual tests as a metric, and in the medical domain, CSR better quantifies perceptual similarity concerning the experts' ratings. We also demonstrate that CSR can significantly improve image quality in two image synthesis tasks. Finally, our extensive results suggest that perceptuality is an emergent property of CSR, which can be adapted to many image domains without requiring annotations.
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Semantic segmentation from aerial views is a vital task for autonomous drones as they require precise and accurate segmentation to traverse safely and efficiently. Segmenting images from aerial views is especially challenging as they include diverse view-points, extreme scale variation and high scene complexity. To address this problem, we propose an end-to-end multi-class semantic segmentation diffusion model. We introduce recursive denoising which allows predicted error to propagate through the denoising process. In addition, we combine this with a hierarchical multi-scale approach, complementary to the diffusion process. Our method achieves state-of-the-art results on UAVid and on the Vaihingen building segmentation benchmark.
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Angluin的L*算法使用会员资格和等价查询了解了常规语言的最低(完整)确定性有限自动机(DFA)。它的概率近似正确(PAC)版本用足够大的随机会员查询替换等效查询,以使答案获得高级信心。因此,它可以应用于任何类型的(也是非规范)设备,可以将其视为合成自动机的算法,该算法根据观测值抽象该设备的行为。在这里,我们对Angluin的PAC学习算法对通过引入一些噪音从DFA获得的设备感兴趣。更确切地说,我们研究盎格鲁因算法是否会降低噪声并产生与原始设备更接近原始设备的DFA。我们提出了几种介绍噪声的方法:(1)嘈杂的设备将单词的分类W.R.T.倒置。具有很小概率的DFA,(2)嘈杂的设备在询问其分类W.R.T.之前用小概率修改了单词的字母。 DFA和(3)嘈杂的设备结合了W.R.T.单词的分类。 DFA及其分类W.R.T.柜台自动机。我们的实验是在数百个DFA上进行的。直言不讳地表明,我们的主要贡献表明:(1)每当随机过程产生嘈杂的设备时,盎格鲁因算法的行为都很好,(2)但使用结构化的噪声却很差,并且(3)几乎肯定是随机性的产量具有非竞争性语言的系统。
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韵律在言语交流中起着至关重要的作用。韵律的声明已被广泛研究。但是,韵律特征不仅被视而不见,而且在视觉上是基于头部和面部运动的视觉上。本报告的目的是提出一种使用虚拟现实检查视听韵律的方法。我们表明,基于虚拟人的动画提供了与真正说话者视频录音相似的运动提示。虚拟现实的使用开辟了新的途径,以检查口头交流的多模式效应。我们讨论了研究人工耳蜗听众中韵律感知的框架中的方法。
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持续学习(CL,有时也称为增量学习)是机器学习的一种味道,在该口味中,通常会放松或省略固定数据分布的通常假设。当天然应用时,例如CL问题中的DNNS时,数据分布的变化会导致所谓的灾难性遗忘(CF)效应:突然丧失了先前的知识。尽管近年来已经为启用CL做出了许多重大贡献,但大多数作品都解决了受监督的(分类)问题。本文回顾了在其他环境中研究CL的文献,例如通过减少监督,完全无监督的学习和强化学习的学习。除了提出一个简单的模式用于分类CL方法W.R.T.他们的自主权和监督水平,我们讨论了与每种设置相关的具体挑战以及对CL领域的潜在贡献。
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