需求分析

About What, not How ?

技術問題留給系統分析和系統設計。

Defining

https://classroom.udacity.com/courses/ud805/lessons/1729809167/concepts/6729086590923

Application Domain : Domain Properties + Requirements Machine Domain : Hardware + Software

Application Domain (交集) Machine Domain = S-Specification

S-Specification:

1. Machine can directly sense. ex: button pressed. Sensor activated.
2. Machine can directly cause. ex: Image on screen. device turn on & off.

Functional v.s Non-Functional Requirement

• Functional : 電梯到指定樓層，計算平方根 ...
• Non-Functional : 安全性，成本，可用性，Adability，Reusability, ....

將 Non-Functional 明確的指出衡量方式，例如電梯必須在 30 秒內到達任何一個樓層 ....

User v.s System Requirement

• User Requirement : For Customer, in Natural Language.
• System Requirement : For Developer, in Detail, Clearly & Rigurously.

Requirement Origin (需求來源)

• Stakeholder (利害關係人) : Customer, User, ...
• Application Domain : Bank, School, ....
• Documentation : Note, paper, ....

但需求分散在各地，甚至有衝突，隱瞞，誤導，....

Analyzing Requirement

https://classroom.udacity.com/courses/ud805/lessons/1729809167/concepts/6729086700923

• Verification (Developer) : list check, complete
• Validation (Customer) : list check, prototyping
• Risk Analysis

Requirements Prioritization (優先順序)

https://classroom.udacity.com/courses/ud805/lessons/1729809167/concepts/6729086710923

mandatory : 強制的；必須履行的 nice to have : 有的話也不錯 sujperfluous : 多餘的,過剩的

Requirements Engineering Process

1. Elicitation : 導出需求
2. Analysis : 分析
3. Modeling : 建模
4. Negotaion : 談判

導出需求 => 談判 => 建模 => 分析 => 修改需求 ....

SRS : Software Requirement Specification

IEEE standard

1. User requirement
2. System requirement

Properties

1. Simple
2. Testable
3. Organized
4. Numbered (編號)