Purpose The purpose of the Stakeholder Requirements Definition Process is to define the requirements for a system that can provide the services needed by user and other stakeholders in a defined environment. It identifies stakeholders,or stakeholder classes,involved with the system through its life cycle,and their needs, expectations,and desires. 酒 It analyzes and transforms these into a common set of stakeholder requirements that express the intended interaction the system will have with its operational environment and that are the reference against which each resulting operational service is validated. INCOSE Sys Eng Handbook System Engineering by J.J.Gao CLGO 6
+ - System Engineering by J. J. Gao 6 Purpose The purpose of the Stakeholder Requirements Definition Process is to define the requirements for a system that can provide the services needed by user and other stakeholders in a defined environment. It identifies stakeholders, or stakeholder classes, involved with the system through its life cycle, and their needs, expectations, and desires. It analyzes and transforms these into a common set of stakeholder requirements that express the intended interaction the system will have with its operational environment and that are the reference against which each resulting operational service is validated
Importance of Requirement Bell Labs and IBM:80%of all product defects are inserted in the requirement definition stage of product development (Hooks and Farray 2001). Software does not fail randomly.Software malfunction is due to design error,which most of the time are due to incomplete/incorrect requirements (Leveson 2012) System Engineering by J.J.Gao CLGO 7
+ - System Engineering by J. J. Gao 7 Importance of Requirement
Importance of Requirement Figure 1-3.Cost of Requirement Errors18 1.000 1,000- 70 60- 50- 40 40 40- 30 30- 20- 15 10 10- 3 0- Requirements Design Coding Development Acceptance Operations Phase Phase Phase Testing Testing Hooks and Farray 2001 System Engineering by J.J.Gao CLGO 8
+ - System Engineering by J. J. Gao 8 Importance of Requirement
Examples of Failures Titanic Sank in the North Atlantic Ocea RMS Titanic Person Car Bus Airbus A380 Queen Mary 2 on 15 April 1912 in first trip Problem of iron rivets Cold water makes iron rivets crispy Not enough lifeboats(Lost 70% of passengers) What is the requirements of this kid of passenger liner? System Engineering by J.J.Gao CLGO
+ - Titanic Sank in the North Atlantic Ocean on 15 April 1912 in first trip Problem of iron rivets Cold water makes iron rivets crispy Not enough lifeboats(Lost 70% of passengers) What is the requirements of this kid of passenger liner? System Engineering by J. J. Gao 9 Examples of Failures
Examples of Failures Tacoma Narrows Bridge Crosswind makes it collapse a Design engineers reuse the requirements of an existing bridge Wrong bridge for the environments Video Who is the stakeholder of this bridge and what is the needs? System Engineering by J.J.Gao 10
+ - Tacoma Narrows Bridge Crosswind makes it collapse Design engineers reuse the requirements of an existing bridge Wrong bridge for the environments Video Who is the stakeholder of this bridge and what is the needs? System Engineering by J. J. Gao 10 Examples of Failures