fraction weight

Today you can get an iPod nano for $179 that’s a fraction of the original iPod’s size and weight, with double the storage, a color display, video playback, and a built-in video camera.

今天你可以只花179美元就能得到一个iPod nano，今天的产品只是最初的iPod大小和重量的一小部分，但是会有最初的两倍的存储容量，彩色的显示屏，能录放而且还有一个内置的摄像头。

The perceptron training rule is based on the idea that weight modification is best determined by some fraction of the difference between target and output.

感知器培训规则是基于这样一种思路—权系数的调整是由目标和输出的差分方程表达式决定。

There are many, but one plausible rule is based on the idea that weight and threshold modification should be determined by a fraction of (t - y).

有很多，不过有一条似乎合理的规则是基于这样一种思想，即权系数和阈值的调整应该由分式(t - y)确定。