PubMed Health⌕ Search

Biomedical subjects

Colin Fyfe

Publications and source records attributed to Colin Fyfe.

3 recordsLinked to original sources

A canonical correlation neural network for multicollinearity and functional data.

We review a recent neural implementation of Canonical Correlation Analysis and show, using ideas suggested by Ridge Regression, how to make the algorithm robust. The network is shown to operate on data sets which exhibit multicollinearity. We develop a second model which not only performs as well on multicollinear data but also on general data sets. This model allows us to vary a single parameter so that the network is capable of performing Partial Least Squares regression (at one extreme) to Canonical Correlation Analysis (at the other)and every intermediate operation between the two. On multicollinear data, the parameter setting is shown to be important but on more general data no particular parameter setting is required. Finally, we develop a second penalty term which acts on such data as a smoother in that the resulting weight vectors are much smoother and more interpretable than the weights without the robustification term. We illustrate our algorithms on both artificial and real data.

Child, Preschool↗

Twinned principal curves.

Principal Curves are extensions of Principal Component Analysis and are smooth curves, which pass through the middle of a data set. We extend the method so that, on pairs of data sets which have underlying non-linear correlations, we have pairs of curves which go through the 'centre' of data sets in such a way that the non-linear correlations between the data sets are captured. The core of the method is to iteratively average the current local projections of the data points which produces an increasingly sparsified set of nodes. The Twinned Principal Curves are generated in three ways: by joining up the nodes in order, by performing Local Canonical Correlation Analysis and by performing Local Exploratory Correlation Analysis (Koetsier et al., 2002). The latter two are shown to improve the forecasting capability of the method but at an increased computational load. We show that it is crucial to terminate the algorithm after a small number of iterations for the first method and investigate several criteria for doing so.

Algorithms↗

A Comparative Study of Two Neural Methods of Exploratory Projection Pursuit.

We investigate two recently proposed methods of performing exploratory data analysis using artificial neural networks: the BCM neuron and the negative feedback network. Our findings are that the BCM neuron performs only a severely limited version of Exploratory Projection Pursuit while the negative feedback network is effective in finding all interesting projections of data. The improved properties of an extension to the basic BCM neuron are analysed. Copyright 1997 Elsevier Science Ltd. All Rights Reserved.

Journal Article↗