在二水準部份因子設計的領域中，「半折疊設計」(Semifolding design)的觀念和技巧在解析度III和IV的設計中已有詳盡的探討，如Mee and peralta(2000)和Ting and hsu(2002)，本研究報告主要是針對16-run, 32-run及64-run解析度IV的設計，利用Ting and hsu(2002)所提之概念與方法，進行半折疊與雙半折疊(Double semifolding)。本研究報告所建議之雙半折疊過程為先將原始設計分成四個部份，然後在對其中一部份進行折疊。本研究報告之表列最佳子集選取的因子組合，礙於篇幅，無法提供，請參閱葉紫君(2002)，報告最後將應用實例來對雙半折疊設計、半折疊設計與全折疊設計做一比較與建議。 In the area of two-level fractional factorial design, the concept and techniques of semifolding have been developed for resolution III and IV designs, e.x., Mee and Peralta (2000) and Ting and Hsu (2002). This research report, however, focuses on 16-run, 32-run, and 64-run resolution IV designs. We apply the semifolding procedure proposed by Ting and Hsu (2002) and extend it to double-semifolding. The procedure we suggest in doing double-semifolding is to block the original design into four sections, and then to fold over on one section only. The "optimal" blocking factors are listed in tables, which can be found in 葉紫君(2002), and the performance of double-semifolding designs in comparisons with that of full foldover designs and semifolding designs are shown by means of examples.