Biomaterial Database

Quasi-objective nonlinear principal component analysis. 2011

Bei-Wei Lu, and Lionel Pandolfo

Department of Earth and Ocean Sciences, University of British Columbia, Canada. blu@eos.ubc.ca

By means of mathematical analysis and numerical experimentation, this study shows that the problems of non-uniqueness of solutions and data over-fitting, that plague the multilayer feedforward neural network for NonLinear Principal Component Analysis (NLPCA), are caused by inappropriate architecture of the neural network. A simplified two-hidden-layer feedforward neural network, which has no encoding layer and no bias term in the mathematical definitions of bottleneck and output neurons, is proposed to conduct NLPCA. This new, compact NLPCA model alleviates the aforementioned problems encountered when using the more complex neural network architecture for NLPCA. The numerical experiments are based on a data set generated from a well-known nonlinear system, the Lorenz chaotic attractor. Given the same number of bottleneck neurons or reduced dimensions, the compact NLPCA model effectively characterizes and represents the Lorenz attractor with significantly fewer parameters than the relevant three-hidden-layer feedforward neural network for NLPCA.

UI	MeSH Term	Description	Entries
D002980	Climate	The longterm manifestations of WEATHER. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Climates
D001272	Atmosphere	The gaseous envelope surrounding a planet or similar body. (From Random House Unabridged Dictionary, 2d ed)	Atmospheres
D016571	Neural Networks, Computer	A computer architecture, implementable in either hardware or software, modeled after biological neural networks. Like the biological system in which the processing capability is a result of the interconnection strengths between arrays of nonlinear processing nodes, computerized neural networks, often called perceptrons or multilayer connectionist models, consist of neuron-like units. A homogeneous group of units makes up a layer. These networks are good at pattern recognition. They are adaptive, performing tasks by example, and thus are better for decision-making than are linear learning machines or cluster analysis. They do not require explicit programming.	Computational Neural Networks,Connectionist Models,Models, Neural Network,Neural Network Models,Neural Networks (Computer),Perceptrons,Computational Neural Network,Computer Neural Network,Computer Neural Networks,Connectionist Model,Model, Connectionist,Model, Neural Network,Models, Connectionist,Network Model, Neural,Network Models, Neural,Network, Computational Neural,Network, Computer Neural,Network, Neural (Computer),Networks, Computational Neural,Networks, Computer Neural,Networks, Neural (Computer),Neural Network (Computer),Neural Network Model,Neural Network, Computational,Neural Network, Computer,Neural Networks, Computational,Perceptron
D017711	Nonlinear Dynamics	The study of systems which respond disproportionately (nonlinearly) to initial conditions or perturbing stimuli. Nonlinear systems may exhibit "chaos" which is classically characterized as sensitive dependence on initial conditions. Chaotic systems, while distinguished from more ordered periodic systems, are not random. When their behavior over time is appropriately displayed (in "phase space"), constraints are evident which are described by "strange attractors". Phase space representations of chaotic systems, or strange attractors, usually reveal fractal (FRACTALS) self-similarity across time scales. Natural, including biological, systems often display nonlinear dynamics and chaos.	Chaos Theory,Models, Nonlinear,Non-linear Dynamics,Non-linear Models,Chaos Theories,Dynamics, Non-linear,Dynamics, Nonlinear,Model, Non-linear,Model, Nonlinear,Models, Non-linear,Non linear Dynamics,Non linear Models,Non-linear Dynamic,Non-linear Model,Nonlinear Dynamic,Nonlinear Model,Nonlinear Models,Theories, Chaos,Theory, Chaos
D025341	Principal Component Analysis	Mathematical procedure that transforms a number of possibly correlated variables into a smaller number of uncorrelated variables called principal components.	Analyses, Principal Component,Analysis, Principal Component,Principal Component Analyses