臺灣博碩士論文加值系統

在軟體重用(reuse)的趨勢下，因商業級軟體組件(COTS)擁有縮短開發時程、降低開發成本及具有運轉經驗的優勢，有愈來愈多業者以商業級軟體組件(COTS)為基礎發展數位系統。COTS不像許多安全關鍵軟體，在開發過程並未針對特定應用領域，嚴格依循特定領域法規或標準，因此使用COTS發展安全關鍵系統的評估要求各有不同。可恃性(Dependability)是軟體獨有的特性，缺乏具體及可量化的評估證據，目前多採用檢核清單的方式，由評估者勾選評估要項是否符合需求，再透過其他討論決定該COTS的符合性，該評估方法對於具有不確定因素的軟體特性恐有遺漏。

本研究提出基於貝式網路(BBN-based)的COTS決策評估方案，以EPRI-106439核電廠安全相關系統應用商業級數位系統的評估與允收指引為例，首先對評估指引進行軟體關鍵特性分析，建立COTS BBN，並透過BBN提供圖形化的表達方式與對不確定事件的推論特性，協助使用者以量化且客觀的方式評估COTS的可恃性，有助於提高決策品質。

In the trend of software reuse, more and more software development vendors develop digital systems based on Commercial off-the Shelf software (COTS) due to the advantages of shortened development time, reduced costs, and past operating experience. However, unlike safety critical software, COTS did not strictly follow specific regulations or standards during development. Using COTS in safety critical systems has different requirements such as safety and dependability. Yet, such quality attributes are hard to obtain quantifiable assessment evidence. Evaluators usually use “reviews and checklists” to assess the dependability of the system. This approach may be controversial and may miss some important requirements for software, in which uncertainty is its intrinsic nature.

We proposed a BBN-based decision making technique for adoption of COTS following EPRI-106439 requirements. EPRI-106439 is a guideline for evaluation and acceptance of commercial grade digital equipment for nuclear safety application. First, we analyzed software critical characteristics of EPRI-10643. Then we proposed a COTS BBN. Through BBN, with graphical presentation and reasoning under uncertainties, our approach can help evaluators to assess the dependability of COTS with a quantified and objectively manner to improve decision quality.

書名頁 i
論文口試委員審定書 ii
授權書 iii
中文摘要 iv
英文摘要 v
誌謝 vi
目錄 vii
表目錄 viii
圖目錄 ix
一、序論 1
二、相關背景研究 2
2.1 EPRI TR-106439 2
2.2 貝式信心網路 4
2.2.1 貝式定理(Bayes'' theorem) 5
2.2.2 BBN範例說明 5
2.2.3 BBN應用文獻探討 7
2.2.4 BBN建模工具 8
2.3 商業級軟體(Commercial off-the Shelf, COTS or OTS) 10
三、研究方法 12
3.1 分析及整理TR-106439 12
3.2 建立COTS貝式信心網路圖 14
3.3 建立評估程序 28
四、案例分析 31
4.1 案例簡介 31
4.2 案例評估說明 32
4.2.1 依COTS BBN蒐集資料做為ZPRL數位保護系統的評估輸入 32
4.2.2 根據取得的新證據，判定評估結果 34
4.2.3 由專家訂定允收界限並做決策 45
五、結論與未來展望 46
六、參考文獻 47
附錄A：COTS BBN與TR-106439關聯對照表 49
附錄B：評估範例證據 53

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