多样性规划算法在单个搜索空间中找到各种不同的起点和目标之间的路径。它们旨在通过在计划查询中重复使用信息来有效地做到这一点。可以在搜索之前或期间计算此信息,并且通常包括有效路径的知识。使用已知的有效途径来解决单个计划查询要比找到全新的解决方案所花费的时间更少。这允许多算法(例如PRM*)在许多问题上胜过诸如RRT*之类的单个算法,但它们的相对性能取决于重复使用的信息。尽管如此,很少有多Qualery计划者明确地寻求最大程度地提高路径重复使用,因此,许多计划者并没有始终如一地超越单寻球替代方案。本文介绍了努力的通知路线图(EIRM*),这是一种几乎渐近的最佳多样性计划算法,明确优先考虑重复使用计算工作。 Eirm*使用非对称双向搜索来识别可能有助于解决单个计划查询的现有路径,然后使用此信息来订购其搜索并减少计算工作。这使其可以在经过测试的抽象和机器人多样性计划问题上的最新计划算法找到最高级别的初始解决方案。
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最佳路径规划是在优化目标的起始和目标之间找到有效状态的问题。知情路径规划算法顺序他们的搜索与特定于问题的知识表达为启发式,并且可以比未表现算法更有效的数量级。启发式最有效的是,当他们准确且计算地廉价才能评估,但这些通常是矛盾的特征。这使得适当的启发式难以满足许多问题。本文提出了两个几乎肯定的渐近最优采样的路径规划算法,以解决这一挑战,自适应地通知的树木(AIT *)和精力知的树木(EIT *)。这些算法使用非对称双向搜索,其中两个搜索彼此连续通知。这允许AIT *和EIT *通过同时计算和利用越来越准确,特定于问题的启发式来改善规划性能。 AIT *和EIT *相对于其他基于样品的算法的好处是在优化路径长度和障碍物间隙的十二个问题上进行了十二个问题。实验表明,AIT *和EIT *优于优化障碍物清除的问题的其他算法,其中先验成本启发式往往是无效的,并且仍然对最小化路径长度的问题表现良好,这种启发式通常是有效的。
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近似贝叶斯深度学习方法对于解决在智能系统中部署深度学习组件时,包括在智能系统中部署深度学习组件的几个问题,包括减轻过度自信的错误并提供增强的鲁棒性,从而超出分发示例。但是,现有近似贝叶斯推理方法的计算要求可以使它们不适合部署包括低功耗边缘设备的智能IOT系统。在本文中,我们为监督深度学习提供了一系列近似贝叶斯推理方法,并在应用这些方法对当前边缘硬件上的挑战和机遇。我们突出了几种潜在的解决方案来降低模型存储要求,提高计算可扩展性,包括模型修剪和蒸馏方法。
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Accurate determination of a small molecule candidate (ligand) binding pose in its target protein pocket is important for computer-aided drug discovery. Typical rigid-body docking methods ignore the pocket flexibility of protein, while the more accurate pose generation using molecular dynamics is hindered by slow protein dynamics. We develop a tiered tensor transform (3T) algorithm to rapidly generate diverse protein-ligand complex conformations for both pose and affinity estimation in drug screening, requiring neither machine learning training nor lengthy dynamics computation, while maintaining both coarse-grain-like coordinated protein dynamics and atomistic-level details of the complex pocket. The 3T conformation structures we generate are closer to experimental co-crystal structures than those generated by docking software, and more importantly achieve significantly higher accuracy in active ligand classification than traditional ensemble docking using hundreds of experimental protein conformations. 3T structure transformation is decoupled from the system physics, making future usage in other computational scientific domains possible.
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Variational autoencoders model high-dimensional data by positing low-dimensional latent variables that are mapped through a flexible distribution parametrized by a neural network. Unfortunately, variational autoencoders often suffer from posterior collapse: the posterior of the latent variables is equal to its prior, rendering the variational autoencoder useless as a means to produce meaningful representations. Existing approaches to posterior collapse often attribute it to the use of neural networks or optimization issues due to variational approximation. In this paper, we consider posterior collapse as a problem of latent variable non-identifiability. We prove that the posterior collapses if and only if the latent variables are non-identifiable in the generative model. This fact implies that posterior collapse is not a phenomenon specific to the use of flexible distributions or approximate inference. Rather, it can occur in classical probabilistic models even with exact inference, which we also demonstrate. Based on these results, we propose a class of latent-identifiable variational autoencoders, deep generative models which enforce identifiability without sacrificing flexibility. This model class resolves the problem of latent variable non-identifiability by leveraging bijective Brenier maps and parameterizing them with input convex neural networks, without special variational inference objectives or optimization tricks. Across synthetic and real datasets, latent-identifiable variational autoencoders outperform existing methods in mitigating posterior collapse and providing meaningful representations of the data.
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Differentiable Architecture Search (DARTS) has attracted considerable attention as a gradient-based Neural Architecture Search (NAS) method. Since the introduction of DARTS, there has been little work done on adapting the action space based on state-of-art architecture design principles for CNNs. In this work, we aim to address this gap by incrementally augmenting the DARTS search space with micro-design changes inspired by ConvNeXt and studying the trade-off between accuracy, evaluation layer count, and computational cost. To this end, we introduce the Pseudo-Inverted Bottleneck conv block intending to reduce the computational footprint of the inverted bottleneck block proposed in ConvNeXt. Our proposed architecture is much less sensitive to evaluation layer count and outperforms a DARTS network with similar size significantly, at layer counts as small as 2. Furthermore, with less layers, not only does it achieve higher accuracy with lower GMACs and parameter count, GradCAM comparisons show that our network is able to better detect distinctive features of target objects compared to DARTS.
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Deep learning techniques with neural networks have been used effectively in computational fluid dynamics (CFD) to obtain solutions to nonlinear differential equations. This paper presents a physics-informed neural network (PINN) approach to solve the Blasius function. This method eliminates the process of changing the non-linear differential equation to an initial value problem. Also, it tackles the convergence issue arising in the conventional series solution. It is seen that this method produces results that are at par with the numerical and conventional methods. The solution is extended to the negative axis to show that PINNs capture the singularity of the function at $\eta=-5.69$
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The Government of Kerala had increased the frequency of supply of free food kits owing to the pandemic, however, these items were static and not indicative of the personal preferences of the consumers. This paper conducts a comparative analysis of various clustering techniques on a scaled-down version of a real-world dataset obtained through a conjoint analysis-based survey. Clustering carried out by centroid-based methods such as k means is analyzed and the results are plotted along with SVD, and finally, a conclusion is reached as to which among the two is better. Once the clusters have been formulated, commodities are also decided upon for each cluster. Also, clustering is further enhanced by reassignment, based on a specific cluster loss threshold. Thus, the most efficacious clustering technique for designing a food kit tailored to the needs of individuals is finally obtained.
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Learning efficient and interpretable policies has been a challenging task in reinforcement learning (RL), particularly in the visual RL setting with complex scenes. While neural networks have achieved competitive performance, the resulting policies are often over-parameterized black boxes that are difficult to interpret and deploy efficiently. More recent symbolic RL frameworks have shown that high-level domain-specific programming logic can be designed to handle both policy learning and symbolic planning. However, these approaches rely on coded primitives with little feature learning, and when applied to high-dimensional visual scenes, they can suffer from scalability issues and perform poorly when images have complex object interactions. To address these challenges, we propose \textit{Differentiable Symbolic Expression Search} (DiffSES), a novel symbolic learning approach that discovers discrete symbolic policies using partially differentiable optimization. By using object-level abstractions instead of raw pixel-level inputs, DiffSES is able to leverage the simplicity and scalability advantages of symbolic expressions, while also incorporating the strengths of neural networks for feature learning and optimization. Our experiments demonstrate that DiffSES is able to generate symbolic policies that are simpler and more and scalable than state-of-the-art symbolic RL methods, with a reduced amount of symbolic prior knowledge.
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Tumor-stroma ratio (TSR) is a prognostic factor for many types of solid tumors. In this study, we propose a method for automated estimation of TSR from histopathological images of colorectal cancer. The method is based on convolutional neural networks which were trained to classify colorectal cancer tissue in hematoxylin-eosin stained samples into three classes: stroma, tumor and other. The models were trained using a data set that consists of 1343 whole slide images. Three different training setups were applied with a transfer learning approach using domain-specific data i.e. an external colorectal cancer histopathological data set. The three most accurate models were chosen as a classifier, TSR values were predicted and the results were compared to a visual TSR estimation made by a pathologist. The results suggest that classification accuracy does not improve when domain-specific data are used in the pre-training of the convolutional neural network models in the task at hand. Classification accuracy for stroma, tumor and other reached 96.1$\%$ on an independent test set. Among the three classes the best model gained the highest accuracy (99.3$\%$) for class tumor. When TSR was predicted with the best model, the correlation between the predicted values and values estimated by an experienced pathologist was 0.57. Further research is needed to study associations between computationally predicted TSR values and other clinicopathological factors of colorectal cancer and the overall survival of the patients.
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