軟體在其生命週期中會因為新增功能、維護等原因改變。然而物件導向軟體在發生改變之後，其內部類別與類別之間的關係也會隨之改變。既有的研究成果指出了程式碼經過長時間的演變，會發生Code Decay的現象，亦即程式模組化程度愈來愈不明顯。為了瞭解軟體改變的特性，本論文將探討軟體模組之間的互動關係，建立軟體類別演進歷史，並藉由現有的設計原則(Design Principles)與耦合強度量測方法來探討軟體改變的分佈情形。本論文修正既有軟體度量方法的不足，將其與耦合強度度量方法結合，以更細微的角度去觀察軟體的改變。並且以統計的方式來說明軟體改變的現象。 Classes in object-oriented software change dynamically with newly added requirements of bugs-fixing. However, with the evolution of software, code usually ends up with a state, called code decay, which is a result of the problem arising from the modularity inside the software. This thesis builds the change history of software classes, and investigates the distribution of software changes based on existing design principles and coupling strength metrics. The A vs. I graph is adopted in this thesis to observe the changes of software.
