诸如GPT-3之类的大型审慎模型通过利用自学学习的学习来学习明显的表现,从而对现代自然语言处理产生了巨大影响,这些表现可以轻易地对各种下游任务进行挑剔。我们通过使用微笑语言构建化学基础模型Chemberta-2来研究将这种进步转移到分子机器学习中的可能性。虽然标记的分子预测任务数据通常很少,但微笑字符串的库很容易获得。在这项工作中,我们通过优化预处理过程来建立Chemberta。我们比较了通过不同的超参数和预处理数据集尺寸的多任务和自我监督预训练的预测,来自PubChem最多77m化合物。据我们所知,77m集合构成了迄今为止用于分子预处理的最大数据集之一。我们发现,通过这些预处理的改进,我们与Moleculenet基准套件上现有的最先进的体系结构具有竞争力。我们分析了预读的改进的程度,转化为下游任务的改进。
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人工智能尚未彻底改变材料和分子的设计。在这种观点中,我们确定了四个障碍,阻碍了原子深度学习,分子科学和高性能计算的整合。我们概述了重点的研究努力,解决这些挑战所提供的机会。
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Molecular machine learning has been maturing rapidly over the last few years.Improved methods and the presence of larger datasets have enabled machine learning algorithms to make increasingly accurate predictions about molecular properties. However, algorithmic progress has been limited due to the lack of a standard benchmark to compare the efficacy of proposed methods; most new algorithms are benchmarked on different datasets making it challenging to gauge the quality of proposed methods. This work introduces MoleculeNet, a large scale benchmark for molecular machine learning. MoleculeNet curates multiple public datasets, establishes metrics for evaluation, and offers high quality open-source implementations of multiple previously proposed molecular featurization and learning algorithms (released as part of the DeepChem
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Recently, deep networks have shown impressive performance for the segmentation of cardiac Magnetic Resonance Imaging (MRI) images. However, their achievement is proving slow to transition to widespread use in medical clinics because of robustness issues leading to low trust of clinicians to their results. Predicting run-time quality of segmentation masks can be useful to warn clinicians against poor results. Despite its importance, there are few studies on this problem. To address this gap, we propose a quality control method based on the agreement across decoders of a multi-view network, TMS-Net, measured by the cosine similarity. The network takes three view inputs resliced from the same 3D image along different axes. Different from previous multi-view networks, TMS-Net has a single encoder and three decoders, leading to better noise robustness, segmentation performance and run-time quality estimation in our experiments on the segmentation of the left atrium on STACOM 2013 and STACOM 2018 challenge datasets. We also present a way to generate poor segmentation masks by using noisy images generated with engineered noise and Rician noise to simulate undertraining, high anisotropy and poor imaging settings problems. Our run-time quality estimation method show a good classification of poor and good quality segmentation masks with an AUC reaching to 0.97 on STACOM 2018. We believe that TMS-Net and our run-time quality estimation method has a high potential to increase the thrust of clinicians to automatic image analysis tools.
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Over the last decade, an approach that has gained a lot of popularity to tackle non-parametric testing problems on general (i.e., non-Euclidean) domains is based on the notion of reproducing kernel Hilbert space (RKHS) embedding of probability distributions. The main goal of our work is to understand the optimality of two-sample tests constructed based on this approach. First, we show that the popular MMD (maximum mean discrepancy) two-sample test is not optimal in terms of the separation boundary measured in Hellinger distance. Second, we propose a modification to the MMD test based on spectral regularization by taking into account the covariance information (which is not captured by the MMD test) and prove the proposed test to be minimax optimal with a smaller separation boundary than that achieved by the MMD test. Third, we propose an adaptive version of the above test which involves a data-driven strategy to choose the regularization parameter and show the adaptive test to be almost minimax optimal up to a logarithmic factor. Moreover, our results hold for the permutation variant of the test where the test threshold is chosen elegantly through the permutation of the samples. Through numerical experiments on synthetic and real-world data, we demonstrate the superior performance of the proposed test in comparison to the MMD test.
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Large Language Models (LLMs) have been the subject of active research, significantly advancing the field of Natural Language Processing (NLP). From BERT to BLOOM, LLMs have surpassed state-of-the-art results in various natural language tasks such as question answering, summarization, and text generation. Many ongoing efforts focus on understanding LLMs' capabilities, including their knowledge of the world, syntax, and semantics. However, extending the textual prowess of LLMs to symbolic reasoning has been slow and predominantly focused on tackling problems related to the mathematical field. In this paper, we explore the use of LLMs for automated planning - a branch of AI concerned with the realization of action sequences (plans) to achieve a goal, typically executed by intelligent agents, autonomous robots, and unmanned vehicles. We introduce Plansformer; an LLM fine-tuned on planning problems and capable of generating plans with favorable behavior in terms of correctness and length with reduced knowledge-engineering efforts. We also demonstrate the adaptability of Plansformer in solving different planning domains with varying complexities, owing to the transfer learning abilities of LLMs. For one configuration of Plansformer, we achieve ~97% valid plans, out of which ~95% are optimal for Towers of Hanoi - a puzzle-solving domain.
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Chatbots, or bots for short, are multi-modal collaborative assistants that can help people complete useful tasks. Usually, when chatbots are referenced in connection with elections, they often draw negative reactions due to the fear of mis-information and hacking. Instead, in this paper, we explore how chatbots may be used to promote voter participation in vulnerable segments of society like senior citizens and first-time voters. In particular, we build a system that amplifies official information while personalizing it to users' unique needs transparently. We discuss its design, build prototypes with frequently asked questions (FAQ) election information for two US states that are low on an ease-of-voting scale, and report on its initial evaluation in a focus group. Our approach can be a win-win for voters, election agencies trying to fulfill their mandate and democracy at large.
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Atrial Fibrillation (AF) is characterized by disorganised electrical activity in the atria and is known to be sustained by the presence of regions of fibrosis (scars) or functional cellular remodeling, both of which may lead to areas of slow conduction. Estimating the effective conductivity of the myocardium and identifying regions of abnormal propagation is therefore crucial for the effective treatment of AF. We hypothesise that the spatial distribution of tissue conductivity can be directly inferred from an array of concurrently acquired contact electrograms (EGMs). We generate a dataset of simulated cardiac AP propagation using randomised scar distributions and a phenomenological cardiac model and calculate contact electrograms at various positions on the field. A deep neural network, based on a modified U-net architecture, is trained to estimate the location of the scar and quantify conductivity of the tissue with a Jaccard index of $91$%. We adapt a wavelet-based surrogate testing analysis to confirm that the inferred conductivity distribution is an accurate representation of the ground truth input to the model. We find that the root mean square error (RMSE) between the ground truth and our predictions is significantly smaller ($p_{val}=0.007$) than the RMSE between the ground truth and surrogate samples.
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自动驾驶汽车必须能够可靠地处理不利的天气条件(例如,雪地)安全运行。在本文中,我们研究了以不利条件捕获的转动传感器输入(即图像)的想法,将其下游任务(例如,语义分割)可以达到高精度。先前的工作主要将其作为未配对的图像到图像翻译问题,因为缺乏在完全相同的相机姿势和语义布局下捕获的配对图像。虽然没有完美对准的图像,但可以轻松获得粗配上的图像。例如,许多人每天在好天气和不利的天气中驾驶相同的路线;因此,在近距离GPS位置捕获的图像可以形成一对。尽管来自重复遍历的数据不太可能捕获相同的前景对象,但我们认为它们提供了丰富的上下文信息来监督图像翻译模型。为此,我们提出了一个新颖的训练目标,利用了粗糙的图像对。我们表明,我们与一致的训练方案可提高更好的图像翻译质量和改进的下游任务,例如语义分割,单眼深度估计和视觉定位。
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对于要表示为歧管上点的2D对象的图像和形状等数据结构,这是常见的。从此类数据中产生消毒的差异私有估计的机制的实用性与它与空间的基础结构和几何形状的兼容性密切相关。特别是,如最近所示,拉普拉斯机理在正面弯曲的歧管上的效用(例如肯德尔的2D形状空间)受到曲率的显着影响。关注歧管上的点样品样本的Fr \'echet平均值的问题,我们利用均值的表征为由平方距离总和组成的目标函数的最小化器,并开发了k-norm梯度机制在Riemannian歧管上,有利于产生接近目标函数零的梯度的值。对于正面弯曲的歧管的情况,我们描述了如何使用平方距离函数的梯度比Laplace机制更好地控制灵敏度,并在数值上在callosa的形状数据集上进行数值演示。还提出了机理在球体上的实用性的进一步说明以及对称正定矩阵的多种示意图。
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