Results 1 - 10 of 8,805

Initial Conditions and Moment Restrictions in Dynamic Panel Data Models

by Richard Blundell, Stephen Bond - Journal of Econometrics , 1998
"... Estimation of the dynamic error components model is considered using two alternative linear estimators that are designed to improve the properties of the standard firstdifferenced GMM estimator. Both estimators require restrictions on the initial conditions process. Asymptotic efficiency comparisons ..."
Abstract - Cited by 2393 (16 self) - Add to MetaCart
comparisons and Monte Carlo simulations for the simple AR(1) model demonstrate the dramatic improvement in performance of the proposed estimators compared to the usual first-differenced GMM estimator, and compared to non-linear GMM. The importance of these results is illustrated in an application

Additive Logistic Regression: a Statistical View of Boosting

by Jerome Friedman, Trevor Hastie, Robert Tibshirani - Annals of Statistics , 1998
"... Boosting (Freund & Schapire 1996, Schapire & Singer 1998) is one of the most important recent developments in classification methodology. The performance of many classification algorithms can often be dramatically improved by sequentially applying them to reweighted versions of the input dat ..."
Abstract - Cited by 1750 (25 self) - Add to MetaCart
Boosting (Freund & Schapire 1996, Schapire & Singer 1998) is one of the most important recent developments in classification methodology. The performance of many classification algorithms can often be dramatically improved by sequentially applying them to reweighted versions of the input

Microalloying Boron Carbide with Silicon to Achieve Dramatically Improved Ductility

by Qi An, William A. Goddard
"... ABSTRACT: Boron carbide (B4C) is a hard material whose value for extended engineering applications such as body armor; is limited by its brittleness under impact. To improve the ductility while retaining hardness, we used density functional theory to examine modifying B4C ductility through microallo ..."
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microalloying. We found that replacing the CBC chain in B4C with Si−Si, denoted as (B11Cp)−Si2, dramatically improves the ductility, allowing a continuous shear to a large strain of 0.802 (about twice of B4C failure strain) without brittle failure. Moreover, (B11C)−Si2 retains low density and high hardness

Secure Web Server Performance Dramatically Improved by Caching SSL Session Keys

by Arthur Goldberg, Robert Buff, Andrew Schmitt - SSL Session Keys,” in Workshop on Internet Server Performance , 1998
"... 12 Performance measurements of secure production Web servers show that reusing cached SSL session keys can significantly reduce client response time. The time to download secure Web documents is reduced between 15% and 50% for 5 geographically diverse U.S. sites. Introduction The importance of el ..."
Abstract - Cited by 26 (2 self) - Add to MetaCart
of electronic commerce is widely acknowledged. Surveys of Web users indicate that poor performance is a major cause of dissatisfaction. We have embarked on a major study of the performance of secure Web communications. Here we present results proving the importance of session key caching for improving end

Mobility increases the capacity of ad-hoc wireless networks

by Matthias Grossglauser, David Tse - IEEE/ACM TRANSACTIONS ON NETWORKING , 2002
"... The capacity of ad-hoc wireless networks is constrained by the mutual interference of concurrent transmissions between nodes. We study a model of an ad-hoc network where n nodes communicate in random source-destination pairs. These nodes are assumed to be mobile. We examine the per-session throughpu ..."
Abstract - Cited by 1220 (5 self) - Add to MetaCart
-session throughput for applications with loose delay constraints, such that the topology changes over the time-scale of packet delivery. Under this assumption, the per-user throughput can increase dramatically when nodes are mobile rather than fixed. This improvement can be achieved by exploiting node mobility as a

The Protein Data Bank

by Helen M. Berman, John Westbrook, Zukang Feng, Gary Gilliland, T. N. Bhat, Helge Weissig, Ilya N. Shindyalov, Philip E. Bourne - Nucleic Acids Res , 2000
"... The Protein Data Bank (PDB; http://www.rcsb.org/pdb/ ) is the single worldwide archive of structural data of biological macromolecules. This paper describes the goals of the PDB, the systems in place for data deposition and access, how to obtain further information, and near-term plans for the futur ..."
Abstract - Cited by 1387 (24 self) - Add to MetaCart
deposited. In the 1980s the number of deposited structures began to increase dramatically. This was due to the improved technology for all aspects of the crystallographic process, the addition of structures determined by nuclear magnetic resonance (NMR) methods, and changes in the community views about data

Dynamic Itemset Counting and Implication Rules for Market Basket Data

by Sergey Brin, Rajeev Motwani, Jeffrey D. Ullman, Shalom Tsur , 1997
"... We consider the problem of analyzing market-basket data and present several important contributions. First, we present a new algorithm for finding large itemsets which uses fewer passes over the data than classic algorithms, and yet uses fewer candidate itemsets than methods based on sampling. We in ..."
Abstract - Cited by 615 (6 self) - Add to MetaCart
investigate the idea of item reordering, which can improve the low-level efficiency of the algorithm. Second, we present a new way of generating "implication rules," which are normalized based on both the antecedent and the consequent and are truly implications (not simply a measure of co

A Simple, Fast, and Accurate Algorithm to Estimate Large Phylogenies by Maximum Likelihood

by Stéphane Guindon, Olivier Gascuel , 2003
"... The increase in the number of large data sets and the complexity of current probabilistic sequence evolution models necessitates fast and reliable phylogeny reconstruction methods. We describe a new approach, based on the maximumlikelihood principle, which clearly satisfies these requirements. The ..."
Abstract - Cited by 2182 (27 self) - Add to MetaCart
. The core of this method is a simple hill-climbing algorithm that adjusts tree topology and branch lengths simultaneously. This algorithm starts from an initial tree built by a fast distance-based method and modifies this tree to improve its likelihood at each iteration. Due to this simultaneous adjustment

Constrained K-means Clustering with Background Knowledge

by Kiri Wagstaff, Claire Cardie, Seth Rogers, Stefan Schroedl - In ICML , 2001
"... Clustering is traditionally viewed as an unsupervised method for data analysis. However, in some cases information about the problem domain is available in addition to the data instances themselves. In this paper, we demonstrate how the popular k-means clustering algorithm can be pro tably modi- ed ..."
Abstract - Cited by 488 (9 self) - Add to MetaCart
to make use of this information. In experiments with arti cial constraints on six data sets, we observe improvements in clustering accuracy. We also apply this method to the real-world problem of automatically detecting road lanes from GPS data and observe dramatic increases in performance. 1.

Sequence analysis Mutual information without the influence of phylogeny or entropy dramatically improves residue contact prediction

by From Selectedworks, Stanley D Dunn, Stanley D Dunn, Lindi M Wahl, Gregory B Gloor, S. D. Dunn, L. M. Wahl, G. B. Gloor , 2008
"... Mutual information without the influence of phylogeny or entropy dramatically improves residue contact prediction ..."
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Mutual information without the influence of phylogeny or entropy dramatically improves residue contact prediction
Results 1 - 10 of 8,805