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University of California, Berkeley

EducationBerkeley, California, United States
About: University of California, Berkeley is a(n) education organization based out in Berkeley, California, United States. It is known for research contribution in the topic(s): Population & Galaxy. The organization has 128244 authors who have published 265680 publication(s) receiving 16824174 citation(s). The organization is also known as: University of California Berkeley & UC Berkeley. more

Topics: Population, Galaxy, Poison control more

Showing all 128244 results

Shizuo Akira2611308320561
Michael Grätzel2481423303599
Michael Karin236704226485
Yi Cui2201015199725
Yi Chen2174342293080
Fred H. Gage216967185732
Rob Knight2011061253207
Hongjie Dai197570182579
Martin White1962038232387
Michael Marmot1931147170338
David J. Schlegel193600193972
Simon D. M. White189795231645
George Efstathiou187637156228
Michael A. Strauss1851688208506
David H. Weinberg183700171424

Open accessJournal ArticleDOI: 10.1023/A:1010933404324
Leo Breiman1Institutions (1)
01 Oct 2001-
Abstract: Random forests are a combination of tree predictors such that each tree depends on the values of a random vector sampled independently and with the same distribution for all trees in the forest. The generalization error for forests converges a.s. to a limit as the number of trees in the forest becomes large. The generalization error of a forest of tree classifiers depends on the strength of the individual trees in the forest and the correlation between them. Using a random selection of features to split each node yields error rates that compare favorably to Adaboost (Y. Freund & R. Schapire, Machine Learning: Proceedings of the Thirteenth International conference, aaa, 148–156), but are more robust with respect to noise. Internal estimates monitor error, strength, and correlation and these are used to show the response to increasing the number of features used in the splitting. Internal estimates are also used to measure variable importance. These ideas are also applicable to regression. more

Topics: Random forest (63%), Multivariate random variable (57%), Random subspace method (57%) more

58,232 Citations

Book ChapterDOI: 10.1007/978-1-4612-4380-9_25
Edward L. Kaplan1, Paul Meier2Institutions (2)
Abstract: In lifetesting, medical follow-up, and other fields the observation of the time of occurrence of the event of interest (called a death) may be prevented for some of the items of the sample by the previous occurrence of some other event (called a loss). Losses may be either accidental or controlled, the latter resulting from a decision to terminate certain observations. In either case it is usually assumed in this paper that the lifetime (age at death) is independent of the potential loss time; in practice this assumption deserves careful scrutiny. Despite the resulting incompleteness of the data, it is desired to estimate the proportion P(t) of items in the population whose lifetimes would exceed t (in the absence of such losses), without making any assumption about the form of the function P(t). The observation for each item of a suitable initial event, marking the beginning of its lifetime, is presupposed. For random samples of size N the product-limit (PL) estimate can be defined as follows: L... more

Topics: Kaplan-Meier Estimate (54%), Population (52%)

51,084 Citations

Open accessJournal ArticleDOI: 10.5555/944919.944937
Abstract: We describe latent Dirichlet allocation (LDA), a generative probabilistic model for collections of discrete data such as text corpora. LDA is a three-level hierarchical Bayesian model, in which each item of a collection is modeled as a finite mixture over an underlying set of topics. Each topic is, in turn, modeled as an infinite mixture over an underlying set of topic probabilities. In the context of text modeling, the topic probabilities provide an explicit representation of a document. We present efficient approximate inference techniques based on variational methods and an EM algorithm for empirical Bayes parameter estimation. We report results in document modeling, text classification, and collaborative filtering, comparing to a mixture of unigrams model and the probabilistic LSI model. more

27,392 Citations

Open accessProceedings Article
03 Jan 2001-
Abstract: We propose a generative model for text and other collections of discrete data that generalizes or improves on several previous models including naive Bayes/unigram, mixture of unigrams [6], and Hof-mann's aspect model, also known as probabilistic latent semantic indexing (pLSI) [3]. In the context of text modeling, our model posits that each document is generated as a mixture of topics, where the continuous-valued mixture proportions are distributed as a latent Dirichlet random variable. Inference and learning are carried out efficiently via variational algorithms. We present empirical results on applications of this model to problems in text modeling, collaborative filtering, and text classification. more

25,546 Citations

David J. Teece1, Gary P. Pisano2, Amy Shuen3Institutions (3)
Abstract: The dynamic capabilities framework analyzes the sources and methods of wealth creation and capture by private enterprise firms operating in environments of rapid technological change. The competitive advantage of firms is seen as resting on distinctive processes (ways of coordinating and combining), shaped by the firm's (specific) asset positions (such as the firm's portfolio of difftcult-to- trade knowledge assets and complementary assets), and the evolution path(s) it has aflopted or inherited. The importance of path dependencies is amplified where conditions of increasing retums exist. Whether and how a firm's competitive advantage is eroded depends on the stability of market demand, and the ease of replicability (expanding intemally) and imitatability (replication by competitors). If correct, the framework suggests that private wealth creation in regimes of rapid technological change depends in large measure on honing intemal technological, organizational, and managerial processes inside the firm. In short, identifying new opportunities and organizing effectively and efficiently to embrace them are generally more fundamental to private wealth creation than is strategizing, if by strategizing one means engaging in business conduct that keeps competitors off balance, raises rival's costs, and excludes new entrants. © 1997 by John Wiley & Sons, Ltd. more

  • Table 1. Paradigms of strategy: Salient characteristics
    Table 1. Paradigms of strategy: Salient characteristics
Topics: Competitive advantage (58%), Resource-based view (57%), Absorptive capacity (56%) more

25,469 Citations

No. of papers from the Institution in previous years

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Institution's top 5 most impactful journals

Social Science Research Network

6.5K papers, 294.6K citations

The Astrophysical Journal

5.1K papers, 542.8K citations


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