In the last few years, various types of machine learning algorithms, such as Support Vector Machine (SVM), Support Vector Regression (SVR), and Non-negative Matrix Factorization (NMF) have been introduced. The kernel approach is an effective method for increasing the classification accuracy of machine learning algorithms. This paper introduces a family of one-parameter kernel functions for improving the accuracy of SVM classification. The proposed kernel function consists of a trigonometric term and differs from all existing kernel functions. We show this function is a positive definite kernel function. Finally, we evaluate the SVM method based on the new trigonometric kernel, the Gaussian kernel, the polynomial kernel, and a convex combination of the new kernel function and the Gaussian kernel function on various types of datasets. Empirical results show that the SVM based on the new trigonometric kernel function and the mixed kernel function achieve the best classification accuracy. Moreover, some numerical results of performing the SVR based on the new trigonometric kernel function and the mixed kernel function are presented.
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The current reinforcement learning algorithm uses forward-generated trajectories to train the agent. The forward-generated trajectories give the agent little guidance, so the agent can explore as much as possible. While the appreciation of reinforcement learning comes from enough exploration, this gives the trade-off of losing sample efficiency. The sampling efficiency is an important factor that decides the performance of the algorithm. Past tasks use reward shaping techniques and changing the structure of the network to increase sample efficiency, however these methods require many steps to implement. In this work, we propose novel reverse curriculum reinforcement learning. Reverse curriculum learning starts training the agent using the backward trajectory of the episode rather than the original forward trajectory. This gives the agent a strong reward signal, so the agent can learn in a more sample-efficient manner. Moreover, our method only requires a minor change in algorithm, which is reversing the order of trajectory before training the agent. Therefore, it can be simply applied to any state-of-art algorithms.
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In this paper, we propose an end-to-end Retrieval-Augmented Visual Language Model (REVEAL) that learns to encode world knowledge into a large-scale memory, and to retrieve from it to answer knowledge-intensive queries. REVEAL consists of four key components: the memory, the encoder, the retriever and the generator. The large-scale memory encodes various sources of multimodal world knowledge (e.g. image-text pairs, question answering pairs, knowledge graph triplets, etc) via a unified encoder. The retriever finds the most relevant knowledge entries in the memory, and the generator fuses the retrieved knowledge with the input query to produce the output. A key novelty in our approach is that the memory, encoder, retriever and generator are all pre-trained end-to-end on a massive amount of data. Furthermore, our approach can use a diverse set of multimodal knowledge sources, which is shown to result in significant gains. We show that REVEAL achieves state-of-the-art results on visual question answering and image captioning.
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This paper presents an algorithm that relies on a series of dense and deep neural networks for passive microwave retrieval of precipitation. The neural networks learn from coincidences of brightness temperatures from the Global Precipitation Measurement (GPM) Microwave Imager (GMI) with the active precipitating retrievals from the Dual-frequency Precipitation Radar (DPR) onboard GPM as well as those from the {CloudSat} Profiling Radar (CPR). The algorithm first detects the precipitation occurrence and phase and then estimates its rate, while conditioning the results to some key ancillary information including parameters related to cloud microphysical properties. The results indicate that we can reconstruct the DPR rainfall and CPR snowfall with a detection probability of more than 0.95 while the probability of a false alarm remains below 0.08 and 0.03, respectively. Conditioned to the occurrence of precipitation, the unbiased root mean squared error in estimation of rainfall (snowfall) rate using DPR (CPR) data is less than 0.8 (0.1) mm/hr over oceans and land. Beyond methodological developments, comparing the results with ERA5 reanalysis and official GPM products demonstrates that the uncertainty in global satellite snowfall retrievals continues to be large while there is a good agreement among rainfall products. Moreover, the results indicate that CPR active snowfall data can improve passive microwave estimates of global snowfall while the current CPR rainfall retrievals should only be used for detection and not estimation of rates.
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强化学习(RL)是一种基于代理的方法,可以教机器人在物理世界中导航。已知收集RL的数据是一项费力的任务,现实世界实验可能会冒险。模拟器以更快,更具成本效益的方式促进培训数据的收集。但是,RL经常需要大量的仿真步骤才能使代理在简单任务上变得熟练。这是基于RL的视觉四面导航字段中普遍的问题,其中状态尺寸通常非常大,动态模型很复杂。此外,渲染图像和获得代理的物理特性在计算上可能很昂贵。为了解决这个问题,我们提出了一个基于Airsim的模拟框架,该框架提供了有效的并行训练。在此框架的基础上,APE-X经过修改,以结合空调环境的分散培训,以利用众多网络计算机。通过实验,我们能够使用上述框架将训练时间从3.9小时减少到11分钟,总共有74个代理和两台网络计算机。可以在https://sites.google.com/view/prl4airsim/home上找到有关我们项目Prl4airsim的更多详细信息和有关我们项目的视频。
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我们提出了IM2NERF,这是一个学习框架,该框架可以预测在野生中给出单个输入图像的连续神经对象表示,仅通过现成的识别方法进行分割输出而受到监督。构建神经辐射场的标准方法利用了多视图的一致性,需要对场景的许多校准视图,这一要求在野外学习大规模图像数据时无法满足。我们通过引入一个模型将输入图像编码到包含对象形状的代码,对象外观代码以及捕获对象图像的估计相机姿势的模型来迈出解决此缺点的一步。我们的模型条件在预测的对象表示上nerf,并使用卷渲染来从新视图中生成图像。我们将模型端到端训练大量输入图像。由于该模型仅配有单视图像,因此问题高度不足。因此,除了在合成的输入视图上使用重建损失外,我们还对新颖的视图使用辅助对手损失。此外,我们利用对象对称性和循环摄像头的姿势一致性。我们在Shapenet数据集上进行了广泛的定量和定性实验,并在开放图像数据集上进行了定性实验。我们表明,在所有情况下,IM2NERF都从野外的单视图像中实现了新视图合成的最新性能。
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使用可能的异质动力学估算时间序列数据的价值风险是一项高度挑战的任务。通常,我们面临着一个小的数据问题,结合了高度的非线性,因此对于经典和机器学习估计算法造成了困难。在本文中,我们提出了使用长期记忆(LSTM)神经网络的新型价值估计器,并将其性能与基准GARCH估计器进行比较。我们的结果表明,即使在相对较短的时间序列中,LSTM也可以用于完善或监视风险估计过程,并以非参数方式正确识别潜在的风险动态。我们对模拟和市场数据的估计器进行了评估,重点是异方差,发现LSTM在模拟数据上表现出与GARCH估算器相似的性能,而在实际市场数据上,它对增加波动性或降低波动性更为敏感,并且优于所有现有的现有估计器在异常率和平均分位数评分方面,价值风险。
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对于现代自治系统来说,可靠的场景理解是必不可少的。当前基于学习的方法通常试图根据仅考虑分割质量的细分指标来最大化其性能。但是,对于系统在现实世界中的安全操作,考虑预测的不确定性也至关重要。在这项工作中,我们介绍了不确定性感知的全景分段的新任务,该任务旨在预测每个像素语义和实例分割,以及每个像素不确定性估计。我们定义了两个新颖的指标,以促进其定量分析,不确定性感知的综合质量(UPQ)和全景预期校准误差(PECE)。我们进一步提出了新型的自上而下的证据分割网络(EVPSNET),以解决此任务。我们的架构采用了一个简单而有效的概率融合模块,该模块利用了预测的不确定性。此外,我们提出了一种新的LOV \'ASZ证据损失函数,以优化使用深度证据学习概率的分割的IOU。此外,我们提供了几个强大的基线,将最新的泛型分割网络与无抽样的不确定性估计技术相结合。广泛的评估表明,我们的EVPSNET可以实现标准综合质量(PQ)的新最新技术,以及我们的不确定性倾斜度指标。
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由于众所周知,强化学习算法是数据密集型的,因此从环境中进行采样观测的任务通常在多个代理之间分配。但是,将这些观察结果从代理转移到中心位置可能会非常昂贵,并且还可以损害每个代理人本地行为政策的隐私。在本文中,我们考虑了一个联合加强学习框架,其中多个代理商协作学习了一个全球模型,而无需共享他们的个人数据和政策。每个代理都维护模型的本地副本,并使用本地采样数据对其进行更新。尽管具有n个代理可以启用n次数据的采样,但尚不清楚它是否导致比例收敛的加速。我们提出了联合版本的On-Policy TD,Off-Policy TD和Q学习,并分析其收敛性。对于所有这些算法,据我们所知,我们是第一个考虑马尔可夫噪声和多个局部更新的人,并证明相对于代理的数量是线性收敛的速度。为了获得这些结果,我们表明联邦TD和Q学习是与马尔可夫噪声联合随机近似的一般框架的特殊情况,并且我们利用该框架提供了适用于所有算法的统一收敛分析。
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根据诊断各种疾病的胸部X射线图像的可观增长,以及收集广泛的数据集,使用深神经网络进行了自动诊断程序,已经占据了专家的思想。计算机视觉中的大多数可用方法都使用CNN主链来获得分类问题的高精度。然而,最近的研究表明,在NLP中成为事实上方法的变压器也可以优于许多基于CNN的模型。本文提出了一个基于SWIN变压器的多标签分类深模型,作为实现最新诊断分类的骨干。它利用了头部体系结构来利用多层感知器(也称为MLP)。我们评估了我们的模型,该模型称为“ Chest X-Ray14”,最广泛,最大的X射线数据集之一,该数据集由30,000多名14例著名胸部疾病的患者组成100,000多个额叶/背景图像。我们的模型已经用几个数量的MLP层用于头部设置,每个模型都在所有类别上都达到了竞争性的AUC分数。胸部X射线14的全面实验表明,与以前的SOTA平均AUC为0.799相比,三层头的平均AUC得分为0.810,其平均AUC得分为0.810。我们建议对现有方法进行公平基准测试的实验设置,该设置可以用作未来研究的基础。最后,我们通过确认所提出的方法参与胸部的病理相关区域,从而跟进了结果。
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