The general principle behind all these techniques is to locate relatively homogeneousparts of a document and group them close to each other in a transformed file.
所有这些技术背后的一般原则是定位文档的相对同构部分，然后在已转换文件中将它们相互组织在一起。
2
But if the region has a strange shape or if a density is not homogeneous, if parts of it are heavier then you will get whatever the weighted average will be.
但如果这区域的形状很特殊，或者密度不均匀，也就是某些部分比较重，那就需要求加权平均值。
3
When the equipment energy is limited, the repeated compaction and the double direction compaction are efficient ways to manufacture homogeneous and high-density powder parts.