arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1507.06346stat.MLcs.LGmath.OC
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谱学习在隐马尔可夫模型辨识中的应用

Evaluation of Spectral Learning for the Identification of Hidden Markov Models

KTH Royal Institute of Technology(KTH皇家理工学院)

Robert Mattila, Cristian R. Rojas, Bo Wahlberg

摘要:

隐马尔可夫模型作为离散时间序列的模型已成功地应用于许多领域。在实际应用中,常常需要对这些模型的参数进行估计。目前主要的辨识方法,如极大似然估计,特别是期望最大化,是迭代的,容易有局部极小值的问题。最近在机器学习文献中提出了一种采用谱子空间方法的非迭代方法。本文评估了该算法的性能,并将其与期望最大化算法的性能进行了比较。我们发现,性能是混合的,它成功地确定了一些系统相对较少的可用观测,但完全失败的一些系统,即使大量的观测是可用的。一个悬而未决的问题是如何解释这种差异。我们提供了一些迹象表明,它可能与如何良好的条件下的一些系统参数。

英文摘要:

Hidden Markov models have successfully been applied as models of discrete time series in many fields. Often, when applied in practice, the parameters of these models have to be estimated. The currently predominating identification methods, such as maximum-likelihood estimation and especially expectation-maximization, are iterative and prone to have problems with local minima. A non-iterative method employing a spectral subspace-like approach has recently been proposed in the machine learning literature. This paper evaluates the performance of this algorithm, and compares it to the performance of the expectation-maximization algorithm, on a number of numerical examples. We find that the performance is mixed; it successfully identifies some systems with relatively few available observations, but fails completely for some systems even when a large amount of observations is available. An open question is how this discrepancy can be explained. We provide some indications that it could be related to how well-conditioned some system parameters are.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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