NO.PZ2015120204000063
问题如下：
A neural network is best described as a technique for machine learning that is:
选项：
A.exactly modeled on the human nervous system.
based on layers of nodes connected by links when the relationships among the features are usually non-linear.
based on a tree structure of nodes when the relationships among the features are linear.
解释：
B is correct.
A is incorrect because neural networks are not exactly modeled on the human nervous system.
C is incorrect because neural networks are not based on a tree structure of nodes when the relationships among the features are linear.
想问一下NN中的summation operator是不是就是把一些non-linear的数据，找到他们之间的一些联系，w1，w2，。。。然后找到他们的线性关系比如Z=w1x1+w2x2+w3x3 之类的，想问一下这个Z作为total net input 算不算这些x1，x2线性关系的一种表达
