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基于高斯 Hermite 正交的多模态非线性滤波

Multimodal nonlinear filtering using Gauss-Hermite Quadrature
课程网址: http://videolectures.net/ecmlpkdd2011_heess_quadrature/  
主讲教师: Nicolas Heess
开课单位: 爱丁堡大学
开课时间: 2011-11-30
课程语种: 英语
中文简介:
在许多滤波问题中,精确的后验状态分布是不易处理的,因此使用更简单的参数形式(例如单高斯分布)来近似。然而,在非线性滤波问题中,后状态分布可以采用复杂的形状甚至变为多模态,因此单个高斯不再足够。这个问题的一个标准解决方案是使用一组独立的滤波器,它们用单个高斯分别表示后验,并共同形成高斯表示的混合。不幸的是,由于过滤器是单独优​​化的,因此不考虑组件之间的相互作用,因此得到的表示通常较差。因此,作为替代方案,我们建议通过将KL发散最小化为真实状态后验来直接优化完全近似混合物分布。为此,我们描述了一种确定性采样方法,它允许我们以合理的计算成本近似地执行难以处理的最小化。我们发现所提出的方法模拟多模态后验分布明显优于独立滤波器组,即使后者允许更多混合成分。我们在主动学习场景中证明了准确表示后验与可处理数量的组件的重要性,其中我们报告了在处理的观察数量和计算时间方面更快的收敛,以及在十维度上更可靠的收敛问题。
课程简介: In many filtering problems the exact posterior state distribution is not tractable and is therefore approximated using simpler parametric forms, such as single Gaussian distributions. In nonlinear filtering problems the posterior state distribution can, however, take complex shapes and even become multimodal so that single Gaussians are no longer sufficient. A standard solution to this problem is to use a bank of independent filters that individually represent the posterior with a single Gaussian and jointly form a mixture of Gaussians representation. Unfortunately, since the filters are optimized separately and interactions between the components consequently not taken into account, the resulting representation is typically poor. As an alternative we therefore propose to directly optimize the full approximating mixture distribution by minimizing the KL divergence to the true state posterior. For this purpose we describe a deterministic sampling approach that allows us to perform the intractable minimization approximately and at reasonable computational cost. We find that the proposed method models multimodal posterior distributions noticeably better than banks of independent filters even when the latter are allowed many more mixture components. We demonstrate the importance of accurately representing the posterior with a tractable number of components in an active learning scenario where we report faster convergence, both in terms of number of observations processed and in terms of computation time, and more reliable convergence on up to ten-dimensional problems.
关 键 词: 滤波问题; 后验状态; 参数形式
课程来源: 视频讲座网
最后编审: 2019-04-02:cwx
阅读次数: 86