軟體維護是企業資訊主管所必須面對的基本工作，也佔據企業資訊部門相當大部分的投資成本，在資訊系統的維護流程中，資訊主管在估算系統維護人力成本與同仁生產力的績效評估上，往往缺乏有效的基準點可提供客觀的角度來衡量合理的工作時程與分配維護人力。
功能點分析（Function Point Analysis, FPA）方法是以使用者觀點來度量所欲進行開發或維護之軟體系統功能性的大小（Functional Size），並加以量化成為功能點數。所謂使用者觀點即是採用使用者所能理解的語言來描述使用者對於軟體系統的功能需求，系統開發者再依據此需求提供解決方案，並以資訊技術來開發軟體系統。由於功能點數是客觀量化軟體功能性大小的度量指標（Software Metric），因此也可以用來作為預估軟體系統開發與維護所需的工作量與成本。
因此本研究的主要目的主要是提出一個結合「功能點分析」的軟體維護流程，用以改善以往純粹以專案經理主觀經驗為主的軟體維護流程。本研究亦以個案公司的實例來驗證所提之流程的可行性與效益。本論文所提出的軟體維護流程具有下列兩項優點：
1. 以往對於軟體維護的績效，無法做出一個量化且客觀的評比，但是導入新的維護程序後，每次的軟體維護需求將會被量化且累積成一個知識庫，可供主管作為參考，因此軟體維護的績效不再是憑經驗或直覺的估算值。
2. 導入本研究所提出的軟體維護流程後，組織可以依據知識庫內容來調整功能點分析方法內參數的設定值，並經所累積的實際數據值來計算出組織軟體維護專案生產力績效的基準比較值（Benchmarking data），以做為同仁績效評估的基準（Baseline）。
經由本研究的個案實證應用發現，企業資訊主管在引進調整後的軟體維護流程後，可以確實掌握每個軟體維護系統功能性大小量化的功能點數、合理地分配維護資源與客觀地評估維護工程師的績效。
關鍵字： 軟體維護、維護流程模式、功能點分析、績效基準。

Software maintenance is a challenge that every IT executive must deal with and it also takes up a major part of IT investment. In the maintenance process of IT systems, all IT executives often find it difficult to objectively estimate a reasonable schedule and man power effort required.
Function Point Analysis (FPA) is a method to measure the functional size of the developed or maintained software system from the user's viewpoint. The functional requirements of the system are expressed in a way that user can understand. Accordingly software developer provides feasible technical solution with the utilization of information technology to develop or maintain the system. Function point is an objective and quantitative functionality size metric of the system, and hence it can be served as a mechanism to estimate the required effort or cost of the developed or maintained software systems.
This thesis proposes a functionality size-based software maintenance process. The proposed process improves the existing process model that is simply based on the subjective experience of project managers. This thesis also conducts an empirical case study to demonstrate the feasibility and real benefit of the proposed maintenance process. The proposed software maintenance process has the following two advantages.
1. A quantitative and objective benchmark is not available for evaluating software maintenance performance in the past. But after the introduction of the proposed maintenance process, each software maintenance request is quantitatively recorded and collected into a knowledge database for IT executives as future references. In the end, the software maintenance performance is no longer evaluated just based on subjective estimates of experience or intuition.
2. After the deployment of the proposed software maintenance process, organizations are able to appropriately adjust the values of parameters in FPA based on the knowledge database. Moreover, the benchmarking data of the performance of organizational software maintenance projects can be calculated accordingly and served as the baseline for objectively evaluate the performance of maintainers.
The empirical case study of adopting the proposed maintenance process reveals that the IT executive can precisely measure the quantitatively functional size of the maintained software systems, reasonably allocate the maintenance resources and objectively evaluate the performance of the maintainers.
Keywords: Software Maintenance, Maintenance Process Model, Function Point Analysis, Baseline Comparison

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