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arXiv 1302.6842cs.AI
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基于枚举高概率独立性的信念更新算法

Belief Updating by Enumerating High-Probability Independence-Based Assignments

Air Force Institute of Technology(空军理工学院);Ben Gurion University of the Negev(内盖夫本-古里安大学)

Eugene Santos, Solomon Eyal Shimony

摘要:

基于独立性(IB)的贝叶斯信念网络分配最初被提出作为溯因解释。IB分配分配更少的变量在溯因解释比计划分配值的所有证据支持的变量。我们使用IB分配来近似贝叶斯信念网络中的边缘概率。最近的工作在贝叶斯网络的信念更新试图近似后验概率找到一个小数目的最高概率完成(或可能证据支持)的分配。在某些假设下,这些赋值的并集中的概率质量足以获得良好的近似。这种方法对于高度连接的网络特别有用,其中最大团大小或割集大小使标准算法难以处理。由于IB作业包含较少的分配变量,因此每个作业中的概率质量大于相应的完整作业。因此,更少的IB赋值就足够了,并且可以更有效地获得良好的近似。IB分配可以用于有效地近似后验节点概率,即使在不遵守先前研究中使用的相当严格的偏度假设的情况下。提出了两种寻找高概率IB分配的算法:一种是最佳优先启发式搜索算法,另一种是专用整数线性规划算法。实验结果表明,该方法对高度连通的信度网络是可行的。

英文摘要:

Independence-based (IB) assignments to Bayesian belief networks were originally proposed as abductive explanations. IB assignments assign fewer variables in abductive explanations than do schemes assigning values to all evidentially supported variables. We use IB assignments to approximate marginal probabilities in Bayesian belief networks. Recent work in belief updating for Bayes networks attempts to approximate posterior probabilities by finding a small number of the highest probability complete (or perhaps evidentially supported) assignments. Under certain assumptions, the probability mass in the union of these assignments is sufficient to obtain a good approximation. Such methods are especially useful for highly-connected networks, where the maximum clique size or the cutset size make the standard algorithms intractable. Since IB assignments contain fewer assigned variables, the probability mass in each assignment is greater than in the respective complete assignment. Thus, fewer IB assignments are sufficient, and a good approximation can be obtained more efficiently. IB assignments can be used for efficiently approximating posterior node probabilities even in cases which do not obey the rather strict skewness assumptions used in previous research. Two algorithms for finding the high probability IB assignments are suggested: one by doing a best-first heuristic search, and another by special-purpose integer linear programming. Experimental results show that this approach is feasible for highly connected belief networks.

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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