Query DAGs: A Practical Paradigm for Implementing Belief Network Inference

Adnan Darwiche; Gregory M. Provan

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arXiv · 1408.1480

Query DAGs: A Practical Paradigm for Implementing Belief Network Inference

Adnan Darwiche·Gregory M. Provan

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Abstract

We describe a new paradigm for implementing inference in belief networks, which relies on compiling a belief network into an arithmetic expression called a Query DAG (Q-DAG). Each non-leaf node of a Q-DAG represents a numeric operation, a number, or a symbol for evidence. Each leaf node of a Q-DAG represents the answer to a network query, that is, the probability of some event of interest. It appears that Q-DAGs can be generated using any of the algorithms for exact inference in belief networks --- we show how they can be generated using clustering and conditioning algorithms. The time and space complexity of a Q-DAG generation algorithm is no worse than the time complexity of the inference algorithm on which it is based; that of a Q-DAG on-line evaluation algorithm is linear in the size of the Q-DAG, and such inference amounts to a standard evaluation of the arithmetic expression it represents. The main value of Q-DAGs is in reducing the software and hardware resources required to utilize belief networks in on-line, real-world applications. The proposed framework also facilitates the development of on-line inference on different software and hardware platforms, given the simplicity of the Q-DAG evaluation algorithm. This paper describes this new paradigm for probabilistic inference, explaining how it works, its uses, and outlines some of the research directions that it leads to.

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BibTeX RIS

Adnan Darwiche, Gregory M. Provan. 2014-08-07. Query DAGs: A Practical Paradigm for Implementing Belief Network Inference. https://arxiv.org/abs/1408.1480

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