上海交通大学：《Systems Engineering 系统工程》课程教学资源（电子讲义）Lecture3 Stakeholder Requirements Definition

IAOTONG UNIVERSITY Systems Engineering Lecture 3 Stakeholder Requirements Definition Instructor(s) Prof.Jianjun Gao Department of Automation School of Electronic Information and Electrical Engineering 2014 Spring

Systems Engineering Instructor(s) + - 2014 Spring Stakeholder Requirements Definition Prof. Jianjun Gao Department of Automation School of Electronic Information and Electrical Engineering Lecture 3

Gao's V-Model Stakeholder Systems Engineering Lifecycle Analysis Overview Managment 个 Requirement Cost and Schedule Commissioning Analysis Management Operations System Verification and Architecture Validation Tradespace System Exploration Integration Human System Factor Design Definition and Safety Optimization System Engineering by J.J.Gao CLGO 2

+ - System Engineering by J. J. Gao 2 Gao’s V-Model Stakeholder Analysis Requirement Analysis System Architecture Tradespace Exploration Design Definition and Optimization System Integration Verification and Validation Commissioning Operations Lifecycle Managment Systems Engineering Overview Cost and Schedule Management Human Factor System Safety

Today's Agenda Importance of Requirements Identify the Stakeholder Techniques:Interview Techniques:Use case Techniques:Brainstorming Concepts of Operations Function Flow Block Diagram System Engineering by J.J.Gao ③cLse 3

+ - 3 Today’s Agenda  Importance of Requirements  Identify the Stakeholder  Techniques: Interview  Techniques: Use case  Techniques: Brainstorming  Concepts of Operations  Function Flow Block Diagram System Engineering by J. J. Gao

Importance of Requirement Figure 2-1.Rush to Err WHAT DO YOU JOSEPH WANT ON YOUR HEATHER- ING- TOMBSTONE? HINK CHING CHIP! CHUNKI TON. TA-DA! 出5 JOSEPH THUD! HEATHER ING TON WHUMP Hooks and Farray 2001 System Engineering by J.J.Gao CLGO 4

+ - System Engineering by J. J. Gao 4 Importance of Requirement

Importance of Requirement ILL NEED TO KNOW FIRST OF ALL I MEAN WHAT ARE YOUR REOUIREMENTS WHAT ARE YOU IM TRYING TO BEFORE I START TO TRYING TO MAKE YOU DESIGN YOU TRYING TO DESIGN THE SOFTWARE ACCOMPLISH? MY SOFTWARE ACCOMPLISH WITH THE SOFTWARE? I WONT KNOW WHAT TRY TO GET THIS I CAN ACCOMPLISH CONCEPT THROUGH YOUR CAN YOU DESIGN UNTIL YOU TELL ME THICK SKULL:THE IT TO TELL YOU WHAT THE SOFTWARE SOFTWARE CAN DO MY REQUIREMENTS? CAN DO. WHATEVER I DESIGN IT TO DO! Scott Adams,Inc/Dist.by UFS,Inc. CLGO System Engineering by J.J.Gao 5

+ - System Engineering by J. J. Gao 5 Importance of Requirement

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