Results 1 - 10 of 293,797

Mediation in experimental and nonexperimental studies: new procedures and recommendations

by Patrick E. Shrout, Niall Bolger - PSYCHOLOGICAL METHODS , 2002
"... Mediation is said to occur when a causal effect of some variable X on an outcome Y is explained by some intervening variable M. The authors recommend that with small to moderate samples, bootstrap methods (B. Efron & R. Tibshirani, 1993) be used to assess mediation. Bootstrap tests are powerful ..."
Abstract - Cited by 696 (4 self) - Add to MetaCart
size is small or suppression is a possibility. Empirical examples and computer setups for bootstrap analyses are provided. Mediation models of psychological processes are popular because they allow interesting associations to be decomposed into components that reveal possible causal mechanisms

Comparison of Multiobjective Evolutionary Algorithms: Empirical Results

by Eckart Zitzler, Lothar Thiele, Kalyanmoy Deb , 2000
"... In this paper, we provide a systematic comparison of various evolutionary approaches to multiobjective optimization using six carefully chosen test functions. Each test function involves a particular feature that is known to cause difficulty in the evolutionary optimization process, mainly in conver ..."
Abstract - Cited by 628 (41 self) - Add to MetaCart
, the experimental results indicate a hierarchy of the algorithms under consideration. Furthermore, the emerging effects are evidence that the suggested test functions provide sufficient complexity to compare multiobjective optimizers. Finally, elitism is shown to be an important factor for improving evolutionary

Propensity Score Matching Methods For Non-Experimental Causal Studies

by Rajeev H. Dehejia, Sadek Wahba , 2002
"... This paper considers causal inference and sample selection bias in non-experimental settings in which: (i) few units in the non-experimental comparison group are comparable to the treatment units; and (ii) selecting a subset of comparison units similar to the treatment units is difficult because uni ..."
Abstract - Cited by 714 (3 self) - Add to MetaCart
This paper considers causal inference and sample selection bias in non-experimental settings in which: (i) few units in the non-experimental comparison group are comparable to the treatment units; and (ii) selecting a subset of comparison units similar to the treatment units is difficult because

The Aurora Experimental Framework for the Performance Evaluation of Speech Recognition Systems under Noisy Conditions

by David Pearce, Hans-günter Hirsch, Ericsson Eurolab Deutschland Gmbh - in ISCA ITRW ASR2000 , 2000
"... This paper describes a database designed to evaluate the performance of speech recognition algorithms in noisy conditions. The database may either be used to measure frontend feature extraction algorithms, using a defined HMM recognition back-end, or complete recognition systems. The source speech f ..."
Abstract - Cited by 534 (6 self) - Add to MetaCart
being used to evaluate alternative proposals for front-end feature extraction. The database has been made publicly available through ELRA so that other speech researchers to evaluate and compare the performance of noise robust algorithms. Recognition results will be presented for the first standard DSR

Learning with local and global consistency.

by Dengyong Zhou , Olivier Bousquet , Thomas Navin Lal , Jason Weston , Bernhard Schölkopf - In NIPS, , 2003
"... Abstract We consider the general problem of learning from labeled and unlabeled data, which is often called semi-supervised learning or transductive inference. A principled approach to semi-supervised learning is to design a classifying function which is sufficiently smooth with respect to the intr ..."
Abstract - Cited by 673 (21 self) - Add to MetaCart
to the intrinsic structure collectively revealed by known labeled and unlabeled points. We present a simple algorithm to obtain such a smooth solution. Our method yields encouraging experimental results on a number of classification problems and demonstrates effective use of unlabeled data.

Discriminative Training Methods for Hidden Markov Models: Theory and Experiments with Perceptron Algorithms

by Michael Collins , 2002
"... We describe new algorithms for training tagging models, as an alternative to maximum-entropy models or conditional random fields (CRFs). The algorithms rely on Viterbi decoding of training examples, combined with simple additive updates. We describe theory justifying the algorithms through a modific ..."
Abstract - Cited by 660 (13 self) - Add to MetaCart
modification of the proof of convergence of the perceptron algorithm for classification problems. We give experimental results on part-of-speech tagging and base noun phrase chunking, in both cases showing improvements over results for a maximum-entropy tagger.

A comparison of document clustering techniques

by Michael Steinbach, George Karypis, Vipin Kumar - In KDD Workshop on Text Mining , 2000
"... This paper presents the results of an experimental study of some common document clustering techniques: agglomerative hierarchical clustering and K-means. (We used both a “standard” K-means algorithm and a “bisecting ” K-means algorithm.) Our results indicate that the bisecting K-means technique is ..."
Abstract - Cited by 613 (27 self) - Add to MetaCart
This paper presents the results of an experimental study of some common document clustering techniques: agglomerative hierarchical clustering and K-means. (We used both a “standard” K-means algorithm and a “bisecting ” K-means algorithm.) Our results indicate that the bisecting K-means technique

Term-weighting approaches in automatic text retrieval

by Gerard Salton, Christopher Buckley - INFORMATION PROCESSING AND MANAGEMENT , 1988
"... The experimental evidence accumulated over the past 20 years indicates that text indexing systems based on the assignment of appropriately weighted single terms produce retrieval results that are superior to those obtainable with other more elaborate text representations. These results depend crucia ..."
Abstract - Cited by 2189 (10 self) - Add to MetaCart
The experimental evidence accumulated over the past 20 years indicates that text indexing systems based on the assignment of appropriately weighted single terms produce retrieval results that are superior to those obtainable with other more elaborate text representations. These results depend

A method for obtaining digital signatures and public-key cryptosystems.

by R L Rivest , A Shamir , L Adleman - Communications of the ACM, , 1978
"... Abstract An encryption method is presented with the novel property that publicly revealing an encryption key does not thereby reveal the corresponding decryption key. This has two important consequences: 1. Couriers or other secure means are not needed to transmit keys, since a message can be encip ..."
Abstract - Cited by 3894 (24 self) - Add to MetaCart
Abstract An encryption method is presented with the novel property that publicly revealing an encryption key does not thereby reveal the corresponding decryption key. This has two important consequences: 1. Couriers or other secure means are not needed to transmit keys, since a message can

TCP Vegas: New techniques for congestion detection and avoidance

by Lawrence S. Brakmo, Sean W. O’malley, Larry L. Peterson - In SIGCOMM , 1994
"... Vegas is a new implementation of TCP that achieves between 40 and 70 % better throughput, with one-fifth to onehalf the losses, as compared to the implementation of TCP in the Reno distributionof BSD Unix. This paper motivates and describes the three key techniques employed by Vegas, and presents th ..."
Abstract - Cited by 600 (3 self) - Add to MetaCart
the results of a comprehensive experimental performance study—using both simulations and measurements on the Internet—of the Vegas and Reno implementations of TCP. 1
Results 1 - 10 of 293,797