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Margin-infused relaxed algorithm (MIRA)〔 〕 is a machine learning algorithm, an online algorithm for multiclass classification problems. It is designed to learn a set of parameters (vector or matrix) by processing all the given training examples one-by-one and updating the parameters according to each training example, so that the current training example is classified correctly with a margin against incorrect classifications at least as large as their loss.〔 〕 The change of the parameters is kept as small as possible. A two-class version called binary MIRA〔 simplifies the algorithm by not requiring the solution of a quadratic programming problem (see below). When used in a one-vs.-all configuration, binary MIRA can be extended to a multiclass learner that approximates full MIRA, but may be faster to train. The flow of the algorithm〔Watanabe, T. et al (2007): "Online Large Margin Training for Statistical Machine Translation". In: ''Proceedings of the 2007 Joint Conference on Empirical Methods in Natural Language Processing and Computational Natural Language Learning'', 764–773.〕〔Bohnet, B. (2009): ''Efficient Parsing of Syntactic and Semantic Dependency Structures''. Proceedings of Conference on Natural Language Learning (CoNLL), Boulder, 67–72.〕 looks as follows: Input: Training examples Output: Set of parameters ← 0, ← 0 for ← 1 to for ← 1 to ← update according to ← end for end for return The update step is then formalized as a quadratic programming〔 problem: Find , so that , i.e. the score of the current correct training must be greater than the score of any other possible by at least the loss (number of errors) of that in comparison to . ==References== 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Margin Infused Relaxed Algorithm」の詳細全文を読む スポンサード リンク
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