为了能够从不完备决策表（IDT）中进行知识发现和数据挖掘，提出一种新的具有对称性的双重可变精度限制容差关系粗集模型（VPLTRST）。
To obtain knowledge and data from incomplete decision table(IDT), the paper presents a new doubly variable precision limited tolerance rough set theory model(VPLTRST).
根据研制的中压共轨电控可变气门系统机构的工作机理，建立了中压共轨电控可变气门系统的仿真模型，试验证明其精度达到了93 % 。
On the basis of the principle of a middle pressure common rail electronically controlled variable valve system, a model has been built for modeling the system and its accuracy achieves 93%.
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