3. NEURAL NETWORK THEORY
The nomenclature used in the neural network literature is different from that used in statistical literature. This sec tion introduces the nomenclature, and explains in detail the backpropagation algorithm (the algorithm used for estima tion of model coefficients).
3.1 Nomenclature
Although the original motivation for the development of neural networks was to model the human brain, most neural networks as they are currently being used bear little resem blance to a biological brain. (It must be pointed out that there is research in the areas of accurately modeling bio logical neurons and the processes of the brain, but these areas will not be discussed further here because this paper is concerned with the use of neural networks in prediction and function estimation.) A neural network is a set of simple computational units that are highly interconnected. The units are also called nodes, and loosely represent the biological neuron. The networks discussed in this paper resemble