TAILIEUCHUNG - Báo cáo khoa học: "The Infinite Tree"

Historically, unsupervised learning techniques have lacked a principled technique for selecting the number of unseen components. Research into non-parametric priors, such as the Dirichlet process, has enabled instead the use of infinite models, in which the number of hidden categories is not fixed, but can grow with the amount of training data. Here we develop the infinite tree, a new infinite model capable of representing recursive branching structure over an arbitrarily large set of hidden categories. Specifically, we develop three infinite tree models, each of which enforces different independence assumptions, and for each model we define a simple direct. | The Infinite Tree Jenny Rose Finkel Trond Grenager and Christopher D. Manning Computer Science Department Stanford University Stanford CA 94305 jrfinkel grenager manning @ Abstract Historically unsupervised learning techniques have lacked a principled technique for selecting the number of unseen components. Research into non-parametric priors such as the Dirichlet process has enabled instead the use of infinite models in which the number of hidden categories is not fixed but can grow with the amount of training data. Here we develop the infinite tree a new infinite model capable of representing recursive branching structure over an arbitrarily large set of hidden categories. Specifically we develop three infinite tree models each of which enforces different independence assumptions and for each model we define a simple direct assignment sampling inference procedure. We demonstrate the utility of our models by doing unsupervised learning of part-of-speech tags from treebank dependency skeleton structure achieving an accuracy of and by doing unsupervised splitting of part-of-speech tags which increases the accuracy of a generative dependency parser from to . 1 Introduction Model-based unsupervised learning techniques have historically lacked good methods for choosing the number of unseen components. For example k-means or EM clustering require advance specification of the number of mixture components. But the introduction of nonparametric priors such as the Dirichletprocess Ferguson 1973 enabled development of infinite mixture models in which the number of hidden components is not fixed but emerges naturally from the training data Antoniak 1974 . 272 Teh et al. 2006 proposed the hierarchical Dirichlet process HDP as a way of applying the Dirichlet process DP to more complex model forms so as to allow multiple group-specific infinite mixture models to share their mixture components. The closely related infinite hidden Markov model is .

TÀI LIỆU LIÊN QUAN
TAILIEUCHUNG - Chia sẻ tài liệu không giới hạn
Địa chỉ : 444 Hoang Hoa Tham, Hanoi, Viet Nam
Website : tailieuchung.com
Email : tailieuchung20@gmail.com
Tailieuchung.com là thư viện tài liệu trực tuyến, nơi chia sẽ trao đổi hàng triệu tài liệu như luận văn đồ án, sách, giáo trình, đề thi.
Chúng tôi không chịu trách nhiệm liên quan đến các vấn đề bản quyền nội dung tài liệu được thành viên tự nguyện đăng tải lên, nếu phát hiện thấy tài liệu xấu hoặc tài liệu có bản quyền xin hãy email cho chúng tôi.
Đã phát hiện trình chặn quảng cáo AdBlock
Trang web này phụ thuộc vào doanh thu từ số lần hiển thị quảng cáo để tồn tại. Vui lòng tắt trình chặn quảng cáo của bạn hoặc tạm dừng tính năng chặn quảng cáo cho trang web này.