Requirements Engineering

Table of contents

• REquirements Engineering
• Feasibility study
• Requirements Elicitation
• Requirements Negotiation
• Requirements Analysis
• Requirements Specification
• Use case Analysis
• Quality Attributes
• Requirements Validation
• Requirements Change Management

 

Requirements Engineering

• Requirements Engineering is a set of activities concerned with identifying and communicating the purpose of a software-intensive system, and the contexts in which it will be used. Hence, RE acts as the brdge between the real world needs of users, customers, and other constituencies affected by a software system, and the capabilities and opportunities afforded by software-intensive technologies
• Requirements engineering is the process of establishing sytem services that the customer requires from a system and constraints unde rwhich it operates and is developed.
• Requirements are descriptions of the system services and constraints, generated from the RE processes.
• System services -> Functional requirements
  
• Constaints -> Non-functional requirements

 

Phased Lifecycle Models

 

Agile Models and RUP

• Basic Philosophy of Agile
  Individual over processes and tools
  Working software over documentation
  Customer collaboration over contract negotiation
  Responding to change over following a plan
  

 

Feasibility Study

• Decides whether or not the proposed system is worth to develop

 

Requirements Elicitation and Analysis

• Called also requirements discovery to find out application domain, services that the system should provide, system's operational constraints

 

Requirements Sepcification

• Write elicited, analyzed, negotiated, prioritized and selected requirements into documents according to the IEEE 830-1998 Standard

 

Requirements Validation

• Demonstrate whether the requirements we defined are what the customer really wants.

 

Requirements Change Management

• The process of managing requirements change during the RE process and the overall system development.
• Traceability is the heart of requirements managements.

 

Requirements Engineering Process

 

Feasibility Study

• To find out if a system development project can be done.

 

Requirements Elicitation

• There sould be a problem that needs solving.
• Vague problem stated by the customer.

 

Stakeholders

• Identify all the people who must be consulted during information acquisition.

 

Things to Rememver When Eliciting Requirements

• Don't Lose Sight of the Goal
• Think Who's Smart
• A Single Statkeholder Can't Sepak for All
• Use Appropriate Elicitation Methods
• Accept Requirements Changes

Manage Elicited Requirements