Paper Presentation

1
Paper Presentation

• Requirements Engineering A Road Map
• Bashar Nuseibeh Steve Easterbrook
• Presented By
• Hatim Shafique

2
Presentation Overview

• Why is it important?
• What is Requirements Engineering?
• Problems Faced in the requirement engineering
  phase
• Cognitive and Social Science Techniques
• RE core activities
• Eliciting requirements
• Modeling and Analyzing requirements
• Communicating requirements
• Agreeing requirements
• Evolving requirements
• Future Research
• Summary

3
Introduction

• RE Important stage in Software Development
• Process of discovering the purpose
• Important part of the engineering process
• What is RE
• Identifying Stakeholders, developers and users
• Analysis, Communication and Validation of
  Requirements
• Challenges
• Numerous distributed stakeholders
• Varying conflicting goals
• Difficulties in articulating these goals
• Evolving Requirements

4
Relative Costs of Fixing Software Faults
200
30
10
4
3
2
1
Requirements
Specification
Planning
Design
Implementation
Integration
Maintenance
5
Cognitive Social Science techniques

• Cognitive psychology
• Provides understanding of difficulties people may
  have in describing their needs.
• Anthropology
• Observing human activities to understand how
  computer system may help or hinder those
  activities.
• Sociology
• Aims to involve those in RE process, who are most
  affected by outcomes.
• Linguistic
• Analyze communication patterns in organization.

6
Context Groundwork

• RE, a Front end activity
• Not always true
• Requirements evolve while system is in operation
• Context Groundwork
• Assessment of Projects Feasibility associated
  Risks
• Identification of suitable RE Process
• Selection of Methods and Techniques for RE
  Activities
• Difference between Method and Technique

7
RE Core Activities

• Eliciting requirements
• Modeling and Analyzing requirements
• Communicating requirements
• Agreeing requirements
• Evolving requirements

8
Eliciting Requirements (1)

• Requirements to Elicit
• Identifying System boundaries
• Identifying stakeholders user classes
• Customers or Clients
• Developers
• Users - novice users, expert users, occasional
  users, disabled users
• Goals Tasks
• Focus on Problem domain
• And needs of stakeholders
• Scenarios Use cases

9
Eliciting Requirements (2)

• Elicitation Techniques
• Traditional techniques
• Questionnaires, surveys, interviews, documents
• Group elicitation techniques
• Prototyping
• Model-driven techniques
• Cognitive techniques
• Contextual techniques
• Need for guidance on use of these Techniques

10
Modeling Analyzing Requirements

• Enterprise Modeling
• Organizational Structure
• Business Rules
• Data Modeling
• Entity-Relationship-Attribute
• Behavioral Modeling
• Functional behavior of Stakeholders.
• Existing
• Required

11
Modeling Analyzing Requirements (2)

• Domain Modeling
• Abstract description of the world
• Advantage Requirement reuse within a domain
• Advantage detailed reasoning about the domain
• Modeling Non-Functional Requirement
• Difficult to measure and test
• Analyzing Requirement Models
• Requirement animation, automated reasoning
• Knowledge based critique, consistency check
  

12
Communicating Requirements

• Requirements Documentation
• Specification of languages notations
• Formal, semi-formal informal language
• Requirements Management
• Readability Traceability
• Requirements origin, development specification
• Documentation Standards
• Pro Guideline for structuring requirement
  documents
• Con Rigid contractual constraints

13
Agreeing Requirements

• Maintain agreement with all stakeholders
• Inspection formal method
• Coherence consistency of the requirements
• Requirement Validation (difficult)
• Knowable question of truth, science like
• Devise experiments to refute current requirements
• conflicting goals among stakeholders
• Conflict resolution among stakeholders
• Win-win approach, negotiation
• Agreement without explicit goals, matrices

14
Evolving Requirements

• Manage Change
• Changing stakeholders needs
• Requirements Scrubbing
• Techniques and tool for configuration management
  and version control
• Exploiting Traceability
• Evaluation of proposed change with existing
  requirements

15
Integrated Requirements Engineering

• Problem Frames
• Identify well-understood problem offers
  well-understood solutions
• Multiple perspective of requirements
• Facilitate req. partition, modeling, analysis
• Automated tools
• DOORS, Prequite Pro, Cradle
• Document req. manage changes

16
A Requirements Engineering Roadmap

• RE became a field of study in early 1990s
• New ideas emerged
• Modeling analysis cannot be isolated from its
  social organizational context
• RE should focus on modeling the property of the
  environment, not functionality
• Resolve conflicting requirements

17
A Requirements Engineering Roadmap (cont.)

• Future Challenges
• Techniques for modeling analyzing properties of
  the environment instead of the behavior of the
  software
• Fill the gap between requirement elicitation and
  formal specification
• Richer models nonfunctional requirements
• Understanding of the impact of Software
  Architecture
• Multidisciplinary training for requirements
  practitioners

18
Summary

• Strengths
• Well structured and well organized paper aiding
  easy understanding.
• Discusses each of the RE core activities in
  detail depicting importance of each of them.
• Research done so far and glimpse on future
  research areas.
• Weaknesses
• Paper account well for the RE activities, but
  fails to explain the RE process.
• Relevance to Embedded Systems
• Author is of the view that software functions in
  conjunction with the system in which it is
  embedded.
• Pervasive computing involving a broad range of
  users.