This paper separates conditional parameter estima- tion, which consistently raises test set accuracy on statistical NLP tasks, from conditional model struc- tures, such as the conditional Markov model used for maximum-entropy tagging, which tend to lower accuracy. Error analysis on part-of-speech tagging shows that the actual tagging errors made by the conditionally structured model derive not only from label bias, but also from other ways in which the independence assumptions of the conditional model structure are unsuited to linguistic sequences. The (...) paper presents new word-sense disambiguation and POS tagging experiments, and integrates apparently conflicting reports from other recent work. (shrink)

Statistical approaches to processing natural language text have become dominant in recent years. This foundational text is the first comprehensive introduction to statistical natural language processing to appear. The book contains all the theory and algorithms needed for building NLP tools. It provides broad but rigorous coverage of mathematical and linguistic foundations, as well as detailed discussion of statistical methods, allowing students and researchers to construct their own implementations. The book covers collocation finding, word sense disambiguation, probabilistic parsing, information retrieval, (...) and other applications. (shrink)

This is the first textbook on pattern recognition to present the Bayesian viewpoint. The book presents approximate inference algorithms that permit fast approximate answers in situations where exact answers are not feasible. It uses graphical models to describe probability distributions when no other books apply graphical models to machine learning. No previous knowledge of pattern recognition or machine learning concepts is assumed. Familiarity with multivariate calculus and basic linear algebra is required, and some experience in the use of probabilities would (...) be helpful though not essential as the book includes a self-contained introduction to basic probability theory. (shrink)

Modern science developed in the interflow of culture between west and east. Combing of pratice technology with philosophic thoughts formed experimental method. Holistic views contacting atomism produced system theory. System thoughts are applicated in the science and engineering of biosystems, and the cencepts of system biomedicine (Kamada T.1992), systems biology (Zieglgansberger W, Tolle TR.1993), system bioengineering and system genetics (Zeng BJ. 1994) were established. From positive to synthetic thoughts, philosophy have been developed ontology, cosmology, organism theories. Structurity is structure logic (...) system founded on entity, develop, exist axioms, tolerance, adaptation, fluctuate, interweave, transform theorems and integrate, adaptation, construct laws. Structurity be discussed on the cosmos, life, culture system, creation, hologram theories of structure ontology, construct mutation, simi-structure organism and entity emergence, symbol implication. From the relation of structure, function and development, the structurity put forward the cycle, spiral, triangle structure stability patterns of self-organization in structure complement each other and stratification, functional couple and interflow bounds growth, coordinativetransformation and holographic symmetry. (shrink)

We present a Chinese word segmentation system submitted to the closed track of Sighan bakeoff 2005. Our segmenter was built using a conditional random field sequence model that provides a framework to use a large number of linguistic features such as character identity, morphological and character reduplication features. Because our morphological features were extracted from the training corpora automatically, our system was not biased toward any particular variety of Mandarin. Thus, our system does not overfit the variety of Mandarin most (...) familiar to the system's designers. Our final system achieved a F-score of.. (shrink)