Learning (k,l)-context-sensitive probabilistic grammars with nonparametric Bayesian approach
نویسندگان
چکیده
Inferring formal grammars with nonparametric Bayesian approach is one of the most powerful for achieving high accuracy from unsupervised data. In this paper, mildly-context-sensitive probabilities, called (k, l)-context-sensitive are defined on context-free (CFGs). CFGs where probabilities rules identified contexts can be seen as a kind dual approaches distributional learning, in which characterize substrings. We handle data sparsity context-sensitive by smoothing effect hierarchical models such Pitman–Yor processes (PYPs). define hierarchy PYPs naturally augmenting infinite PCFGs. The blocked Gibbs sampling known to effective inferring show that, modifying inside able applied probabilistic grammars. At same time, we that time complexity CFG $$O(|V|^{l+3}|w|^3)$$ each sentence w, V set nonterminals. Since it computationally too expensive iterate sufficient times especially when |V| not small, some alternative algorithms required. Therefore, propose new method composite sampling, procedure separated into sub-procedures nonterminals and derivation trees. Finally, demonstrate inferred 0)-context-sensitive achieve lower perplexities than other language PCFGs, n-grams, HMMs.
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ژورنال
عنوان ژورنال: Machine Learning
سال: 2021
ISSN: ['0885-6125', '1573-0565']
DOI: https://doi.org/10.1007/s10994-021-06034-2