現有判讀蛋白質二級結構螺旋體中心軸幾何特徵的六種方法分別為parametric least-squares method, moment matrix, cylindrical fit, cross-product of triad bisector, rotational transformation method, and Helix Analysis﹙HELANAL﹚。但是除了HELANAL將蛋白質螺旋體中心軸分成直線、曲線和扭結型外，其他的都針對直線型作判斷。HELANAL應用最小平方法做統計分析，再藉以歸類該蛋白質螺旋體的類型。然而，其分析的結果並不獨立於選用的座標系統。鑑此，本研究將使用直交殘差最小平方法﹙total least squares analysis, TLS﹚改善現有方法的缺點，開發獨立於座標系統的蛋白質螺旋體幾何特徵判讀方法。我們並且比較TLS和HELANAL判讀的結果。

　　Six methods, namely parametric least-squares method, moment matrix, cylindrical fit, cross-product of triad bisector, rotational transformation method, and helix analysis (HELANAL) , have been explored for geometric characterization of a protein helix. While HELANAL distinguishes among linear, curved, and kinked helix, all the other methods assume only linear ones. Unfortunately, HELANAL employs linear regression analysis making the results dependent of the coordinate system. For the remedy, we explore total least squares analysis (TLS) making results independent from the coordinate system. The thesis presents the TLS method with demonstration examples. TLS results are compared with those obtained by HELANAL.

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