نتایج جستجو برای: الگوریتم projection pursuit

تعداد نتایج: 102603  

2012
Haleh Safavi Chein-I Chang Antonio J. Plaza

Dimensionality Reduction (DR) has found many applications in hyperspectral image processing. This book chapter investigates Projection Pursuit (PP)-based Dimensionality Reduction, (PP-DR) which includes both Principal Components Analysis (PCA) and Independent Component Analysis (ICA) as special cases. Three approaches are developed for PP-DR. One is to use a Projection Index (PI) to produce pro...

2007
Satoshi Kuriki Akimichi Takemura

The projection pursuit index defined by a sum of squares of the third and the fourth sample cumulants is known as the moment index proposed by Jones and Sibson (1987). The limiting distribution of the maximum of the moment index under the null hypothesis that the population is multivariate normal is shown to be the maximum of a Gaussian random field with a finite Karhunen-Loève expansion. An ap...

1998
James V Stone John Porrill

Independent component analysis (ICA) and projection pursuit (PP) are two related techniques for separating mixtures of source signals into their individual components. These rapidly evolving techniques are currently nding applications in speech separation, ERP, EEG, fMRI, and low-level vision. Their power resides in the simple and realistic assumption that diierent physical processes tend to ge...

2004
Pedro Galeano Daniel Peña Ruey S. Tsay

This article uses Projection Pursuit methods to develop a procedure for detecting outliers in a multivariate time series. We show that testing for outliers in some projection directions could be more powerful than testing the multivariate series directly. The optimal directions for detecting outliers are found by numerical optimization of the kurtosis coefficient of the projected series. We pro...

2007
Stéphane Girard Serge Iovleff S. Iovleff

Auto-associative models have been introduced as a new tool for building nonlinear Principal component analysis (PCA) methods. Such models rely on successive approximations of a dataset by manifolds of increasing dimensions. In this chapter, we propose a precise theoretical comparison between PCA and autoassociative models. We also highlight the links between auto-associative models, projection ...

2001
Rosa M. Figueras Pierre Vandergheynst

Matching Pursuit is a greedy algorithm that decomposes any signal into a linear expansion of waveforms taken from a redundant dictionary. Computing the projection of the signal on every element of the basis has a high computational cost. To reduce this computational cost, optimized computational error minimization methods have to be found. Genetic Algorithms have shown to be a good tool to this...

1999
Simone Borra Agostino Di Ciaccio

Recently, many authors have proposed new algorithms to improve the accuracy of certain classifiers on artificial and real data sets. The goal is to assemble a collection of individual classifiers based on resampling of data set. Bagging (Breiman, 1996) and AdaBoost (Freund & Schapire, 1997) are the most used procedures: the first fits many classifiers to bootstrap samples of data and classifies...

2006
Pedro GALEANO Daniel PEÑA Ruey S. TSAY

In this article we use projection pursuit methods to develop a procedure for detecting outliers in a multivariate time series. We show that testing for outliers in some projection directions can be more powerful than testing the multivariate series directly. The optimal directions for detecting outliers are found by numerical optimization of the kurtosis coefficient of the projected series. We ...

2003
Hung-Man Ngai Jian Zhang JIAN ZHANG

A natural multivariate extension of the two-sided cumulative sum chart is proposed via projection pursuit. A modification is given for improving its performance for the special situation in which the process mean is already shifted at the time the charting begins. Simulation studies show that the new charts have slightly better performance than the competing charts (MC1, MEWMA1 and MEWMA2) in t...

Journal: :IEEE transactions on neural networks 1994
Jenq-Neng Hwang Shyh-Rong Lay Martin Mächler R. Douglas Martin Jim Schimert

We study and compare two types of connectionist learning methods for model-free regression problems: 1) the backpropagation learning (BPL); and 2) the projection pursuit learning (PPL) emerged in recent years in the statistical estimation literature. Both the BPL and the PPL are based on projections of the data in directions determined from interconnection weights. However, unlike the use of fi...

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