hw1-V&V

2017-09-25(一）

Advanced Software Engineering Hw1

@author:顏慷

@Version:V1, 2017-09-24

Questions:

• 1.Ｗhat is validation?

• 2.When should validation should be done?

• 3.What kind of standard you already know?

• 4.What is verification?

• 5.When should verification should be done?

• 6.What kind of standard you already know?

Q1:Ｗhat is validation?

• 根據Oxford字典，validation解釋為the action of checking or proving the validity or accuracy of something，validation是一種檢視或證明某件事的精準性、有效性的動作，

• 而軟體工程課本的定義：Software validation is the process of checking that the system and conforms to its specification and it meets the real needs of the users of the system. 而validation的目的確認軟體能符合顧客的期待，通常會問團隊：Are we building the right product?

Q2:When should validation should be done?

• 在軟體開發時，有4個核心process，分別是software specification、software development、software validation、and software evolution.

• 而validation的時期並不固定，會依造software的類型調整，舉例來說，有些軟體適合waterfall model開發，那麼process就會有固定的順序，通常就是排在development後，做檢驗，但有些軟體(eg.E-commerce system) specification, development, and validation are interleaved rather than separate.他的時段就不見得是固定在development後面。

Q3:What kind of standard you already know?

在requirement validation篇章提到，此部分的process要確認requirement符合使用者需求，所以有以下五種確認方向。

• Validity checks:確認requirement是否有效反應使用者需求

• Consistency checks:確認requirement在document中是否衝突，以免影響軟體的一致性

• Completeness checks: 確認requirement document 要包括所有系統使用者的功能與限制

• Realism checks: 確認requirement能在on time and on budget情況下能夠成功實作出來

• Verifiability:減少顧客與承包商之間的分歧風險，所以系統要能被檢驗與証實

Q4:What is verification?

根據oxford字典，verification解釋為the process of establishing the truth , accuracy , or validity of something，建立某件事的正確性、精準性的流程，在軟體工程領域是為了確認能否把事情做對， 另外在goal的部分，the aim of verification is to check the software meets its stated functional and non-functional requirement. verification 與validation兩者在不同維度，前者像是build product right; 後者聚焦在build right product.

Q5:When should verification should be done?

• 首先，是在software testing中，課本提到validation and verification may involve software inspections and review. inspections and reviews analyze and check models ,the program source code, and even system tests.（source code主要由verification檢驗）

• 第二，在transformational development process中, formal verification demonstrate that implementation errors will not dependability of system.

Q6:What kind of standard you already know?

根據IEEE Standard for System and Software Verification and Validation， 提到V & V process include the analysis, evaluation, review, inspection, assessment, and testing of products. 以上六個為verification的standard.