Xem 1-20 trên 1236 kết quả Randomize
  • Tham khảo luận văn - đề án 'luận văn: tìm hiểu phương pháp phân đoạn ảnh dựa trên rwr (random walker restart)', luận văn - báo cáo, công nghệ thông tin phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả

    pdf47p samsung_12 06-05-2013 35 10   Download

  • This chapter is of an introductory nature, its purpose being to indicate some concepts and results from the theory of probability which are used in later chapters . Most of these are contained in Chapters 1-9 of Gnedenko [47], and will therefore be cited without proof. The first section is somewhat isolated, and contains a series of results from the foundations of the theory of probability. A detailed account may be found in [76], or in Chapter I of [31] . Some of these will not be needed in the first part of the book, in which attention is confined to independent random variables ....

    pdf0p denngudo 21-06-2012 26 5   Download

  • Dedicated to the memory of Gert Kjærg˚ Pedersen ard Abstract In the process of developing the theory of free probability and free entropy, Voiculescu introduced in 1991 a random matrix model for a free semicircular system. Since then, random matrices have played a key role in von Neumann algebra theory (cf. [V8], [V9]). The main result of this paper is the follow(n) (n) ing extension of Voiculescu’s random matrix result: Let (X1 , . . . , Xr ) be a system of r stochastically independent n × n Gaussian self-adjoint random matrices as in Voiculescu’s random matrix paper...

    pdf66p noel_noel 17-01-2013 22 4   Download

  • Most approaches to topic modeling assume an independence between documents that is frequently violated. We present an topic model that makes use of one or more user-specified graphs describing relationships between documents. These graph are encoded in the form of a Markov random field over topics and serve to encourage related documents to have similar topic structures. Experiments on show upwards of a 10% improvement in modeling performance. of the form of the distance metric used to specify the edge potentials. ...

    pdf4p hongphan_1 15-04-2013 17 4   Download

  • We take a critical look at the relationship between the security of cryptographic schemes in the Random Oracle Model, and the security of the schemes that result from implementing the random oracle by so called \cryptographic hash functions". The main result of this paper is a negative one: There exist signature and encryption schemes that are secure in the Random Oracle Model, but for which any implementation of the random oracle results in insecure schemes.

    pdf37p tai_lieu2014 11-04-2014 23 4   Download

  • We establish three identities involving Dyck paths and alternating Motzkin paths, whose proofs are based on variants of the same bijection. We interpret these identities in terms of closed random walks on the halfline. We explain how these identities arise from combinatorial interpretations of certain properties of the -Hermite and -Laguerre ensembles of random matrix theory. We conclude by presenting two other identities obtained in the same way, for which finding combinatorial proofs is an open problem....

    pdf16p thulanh5 12-09-2011 32 3   Download

  • Consider the problem of finding a large induced acyclic subgraph of a given simple digraph D = (V,E). The decision version of this problem is NP-complete and its optimization is not likely to be approximable within a ratio of O(n) for some  0. We study this problem when D is a random instance. We show that, almost surely, any maximal solution is within an o(ln n) factor from the optimal one. In addition, except when D is very sparse (having n1+o(1) edges), this ratio is in fact O(1). Thus, the optimal solution can be approximated in a much better way over random instances....

    pdf6p thulanh5 12-09-2011 17 3   Download

  • Tham khảo sách 'probability examples c-3 random variables ii', khoa học tự nhiên, toán học phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả

    pdf116p sn_buon 29-11-2012 23 3   Download

  • Tham khảo sách 'probability examples c-4 random variables iii', khoa học tự nhiên, toán học phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả

    pdf113p sn_buon 29-11-2012 27 3   Download

  • Conditional Random Fields (CRFs) have been applied with considerable success to a number of natural language processing tasks. However, these tasks have mostly involved very small label sets. When deployed on tasks with larger label sets, the requirements for computational resources mean that training becomes intractable. This paper describes a method for training CRFs on such tasks, using error correcting output codes (ECOC). A number of CRFs are independently trained on the separate binary labelling tasks of distinguishing between a subset of the labels and its complement. ...

    pdf8p bunbo_1 17-04-2013 18 3   Download

  • In this paper, we introduce a method of extending the domain of a random mapping admitting the series expansion. This method is based on the convergence of certain random series. Some conditions under which a random mapping can be extended to apply to all $X$ - valued random variables will be presented. AMS Subject classification 2000: Primary $60H05$; Secondary: $60B11$, $60G57$, $60K37$, $37L55$.

    pdf12p tuanlocmuido 19-12-2012 12 2   Download

  • Tham khảo bài viết 'báo cáo " an application of random process for controlled object identification with traffic delay problem "', luận văn - báo cáo phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả

    pdf7p tuanlocmuido 19-12-2012 16 2   Download

  • This paper presents a joint optimization method of a two-step conditional random field (CRF) model for machine transliteration and a fast decoding algorithm for the proposed method. Our method lies in the category of direct orthographical mapping (DOM) between two languages without using any intermediate phonemic mapping. In the two-step CRF model, the first CRF segments an input word into chunks and the second one converts each chunk into one unit in the target language. In this paper, we propose a method to jointly optimize the two-step CRFs and also a fast algorithm to realize it. ...

    pdf6p hongdo_1 12-04-2013 15 2   Download

  • Frequency distribution models tuned to words and other linguistic events can predict the number of distinct types and their frequency distribution in samples of arbitrary sizes. We conduct, for the first time, a rigorous evaluation of these models based on cross-validation and separation of training and test data. Our experiments reveal that the prediction accuracy of the models is marred by serious overfitting problems, due to violations of the random sampling assumption in corpus data. We then propose a simple pre-processing method to alleviate such non-randomness problems. ...

    pdf8p hongvang_1 16-04-2013 22 2   Download

  • Recent work on Conditional Random Fields (CRFs) has demonstrated the need for regularisation to counter the tendency of these models to overfit. The standard approach to regularising CRFs involves a prior distribution over the model parameters, typically requiring search over a hyperparameter space. In this paper we address the overfitting problem from a different perspective, by factoring the CRF distribution into a weighted product of individual “expert” CRF distributions. We call this model a logarithmic opinion pool (LOP) of CRFs (LOP-CRFs).

    pdf8p bunbo_1 17-04-2013 16 2   Download

  • In this paper, we explore the power of randomized algorithm to address the challenge of working with very large amounts of data. We apply these algorithms to generate noun similarity lists from 70 million pages. We reduce the running time from quadratic to practically linear in the number of elements to be computed.

    pdf8p bunbo_1 17-04-2013 15 2   Download

  • This paper describes discriminative language modeling for a large vocabulary speech recognition task. We contrast two parameter estimation methods: the perceptron algorithm, and a method based on conditional random fields (CRFs). The models are encoded as deterministic weighted finite state automata, and are applied by intersecting the automata with word-lattices that are the output from a baseline recognizer. The perceptron algorithm has the benefit of automatically selecting a relatively small feature set in just a couple of passes over the training data. ...

    pdf8p bunbo_1 17-04-2013 14 2   Download

  • The detection of prosodic characteristics is an important aspect of both speech synthesis and speech recognition. Correct placement of pitch accents aids in more natural sounding speech, while automatic detection of accents can contribute to better wordlevel recognition and better textual understanding. In this paper we investigate probabilistic, contextual, and phonological factors that influence pitch accent placement in natural, conversational speech in a sequence labeling setting.

    pdf7p bunbo_1 17-04-2013 9 2   Download

  • In the past decade, the radial artery has frequently been used for coronary bypass surgery despite concern regarding the possibility of graft spasm. Graft patency is a key predictor of long-term survival. We therefore sought to determine the relative patency rate of radial-artery and saphenous-vein grafts in a randomized trial in which we controlled for bias in the selection of patients and vessels. methods We enrolled 561 patients at 13 centers. The left internal thoracic artery was used to bypass the anterior circulation....

    pdf9p muakhuya 07-07-2012 32 1   Download

  • Let us consider the composed random variable η = k=1 ξk , where ξ1 , ξ2 , ... are independent identically distributed random variables and ν is a positive value random, independent of all ξk . In [1] and [2], we gave some the stabilities of the distribution function of η in the following sense: the small changes in the distribution function of ξ k only lead to the small changes in the distribution function of η. In the paper, we investigate the distribution function of η when we have the small changes of the distribution of ν. ...

    pdf6p tuanlocmuido 19-12-2012 19 1   Download


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