13. 資料庫管理系統在更新資料前後，若符合預設條件(如CASCADE 參考行動)即會自動執行一種程序，這種程序稱為 __(17)__ 。

3. (10%) The feedback system in Fig. 3 has an open-loop amplifier \( A{2}(s) = A{0} / (1 + (s / \omega{0})) \), where \( s = j\omega \) and \( \omega \) is the frequency, \( A{0} \) and \( \omega{0} \) are the dc gain and pole frequency of the open-loop amplifier \( A{1} \), respectively. Derive the close-loop transfer function of \( Y(s) / X(s) \)?