标题: | 双边规格多品质特性制程能力指标CpkT的信赖下界 Lower Confidence Bound for Process Capability Index CpkT with Multiple Characteristics |
作者: | 吴彦呈 Wu, Yen-Cheng 彭文理 工业工程与管理学系 |
关键字: | 制程能力分析;多品质特性;双边规格;信赖下界;Process Capability Index;Multiple Characteristics;Two-Sided Specification;Lower Confidence Bound |
公开日期: | 2011 |
摘要: | 制程能力指标经常被用来衡量制程制造产品符合规格的能力,不仅是提供品质保证的工具,也是提供品质改善方面的一个方针。尤其指标Cpk是目前制造业中使用最多、最广泛的指标。现今高科技制程具有多品质特性,但Cpk仅适用于制程只有单一产品品质特性的时候。为了能更精确的得到多品质特性制程的良率Pearn (2011) 等学者由Cpk推广出新指标CpkT。本文中我们考虑CpkT的常态近似分配,用模拟方法检测其误差,再根据误差大小决定适当的样本数。接着我们在适当的样本数的情况下,使用四种Bootstrap方法模拟出信赖下界,然后根据覆盖率与平均数,与近似分配产生的信赖下界做比较。 Process capability indices (PCIs) have been proposed in the manufacturing industry to provide yield measures on process capability, which are effective tools for quality assurance and guidance for process improvement. In particular, the index Cpk is the most popular capability index widely used in the manufacturing industry. Nowadays, high-technology processes have a variety of quality characteristics; however, the index Cpk is only investigated the process with single characteristic. In order to obtain accurate yield assessment for processes with multiple characteristics, a new capability index CpkT, which is a generalization of the index Cpk, has been proposed. In this thesis, we consider a normal approximation distribution of CpkT, and conduct a simulation method to detect the distribution. For the purpose of measuring the accuracy of the approximate distribution of CpkT, a nonparametric but computer intensive method called the bootstrap is used to obtain a lower confidence bound. Also a comparison between the bootstrap and approximate distribution based on coverage rate and mean of lower confidence bound are executed. |
URI: | http://140.113.39.130/cdrfb3/record/nctu/#GT079933539 http://hdl.handle.net/11536/50104 |
显示于类别: | Thesis |