我在网上有看到关于Ｐｕｓｈ／Ｐｕｌｌ（推式与拉式生产）系统的分类，一种是垂直型，一种是水平型的，但是我却看不懂这两种型有什么区别，希望大家帮我解答一下！
Hybrid push/pull production systems may be classified into two categories, Vertically integrated systems consist of two levels, an upper level push-type production control system and a lower level pull-type production control system.
A horizontally integrated hybrid production system (HIHPS) consists of a series of push stations followed by a series of pull stations with semi-finished product stored at the transition point. In this research a horizontally integrated system is considered.
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单从这段话看，垂直型的就是一个push一个pull, 水平型的是多个push多个pull + 中间半成品节点