对称差分

symmetric difference───[数]对称差分（等于Booleansum）

symmetric differences───[数]对称差分（等于Booleansum）

statistical difference───统计差异

potential difference───n.[物]势差，[物]位差

asymmetrical warfare───n.不对称战争，不对等作战

imperial preference───帝国特惠制

potential differences───n.[物]势差，[物]位差

difference of anchorage properties between the symmetrical and unsymmetrical transverse ribbed rebar was studied considering improving materials' usage and anchorage properties by pull-out test.───从提高材料使用性能一锚固性能出发采用拉拔试验研究了横肋对称和横肋非对称钢筋的锚固性能的区别。

anchorage properties between the symmetrical and unsymmetrical ribbed rebar had no obvious difference.───对称和横肋非对称钢筋的粘结锚固性能无明显差异。

The paper introduces several methods for vision-surveillance using background subtraction, frame-difference method, symmetrical differencing and a method based on RGB image.───介绍了在视觉监控领域经常用到的几种运动人体检测算法，如背景减除法、帧差法、对称差分法、基于RGB 图像的运动检测法。