Introduction - If you have any usage issues, please Google them yourself
This article reviews existing algorithmic work, shows how a given data
set can be examined to determine whether a conceptually more demanding NLPCA
model is required and lists developments of NLPCA algorithms. Finally, the paper
outlines problem areas and challenges that require future work to mature the
NLPCA research field.
Developments and Applications of Nonlinear Principal Component Analysis–a Review 2008.pdf