Benefits of a Requirements Driven Development Approach

1
Benefits of a Requirements Driven Development
Approach

• V.K.Kripanand
• Telelogic

2
Challenges

• Product
• Product complexity is rapidly increasing
• Scope is beyond the mind of any individual
• Complex interactions require inputs from many
  disciplines
• Increased technology turnover - more solution
  possibilities
• Employee turnover drives a need to record
  rationale for decisions
• Competition demands
• Reduced development cycle times
• Reduced development costs - increased reuse
• Effective flowdown of the Voice of the Customer
• Customers expect
• A documented, capable, and controlled development
  process (SEI, CMM)
• 100 traceability and verification coverage

3
Challenges

• Companies are challenged with
• Lesser Delivery times
• Strong Competition
• Paradox of Quality, cost and Time
• Conformance to standards
• DO-178B, MISRA
• A host of Telecom standards
• Quality
• Not an end stage activity
• Is to be embedded at every stage of development
• A must have to sustain in the market

4
It isn't that they can't see the solution.It is
that they can't see the problem. Gilbert Keith
Chesterton, author, 1874 - 1936 AD
5
Quality and Requirements

• Quality conformance to requirements
• Requirements management delivering quality
  throughout the life-cycle

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The V-Model

Statement of need

Operational use

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Requirements at every level

Statement of need

Operational use

validating the product




Acceptance
Stakeholder


Requirements
test

satisfies
verifying the system



System
System


Requirements
test

satisfies

qualifying the subsystems


Subsystem
Subsystem


Requirements
test

satisfies

qualifying components


Component
Component


Requirements
test
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Requirements Driven Development

• A methodology to help companies build Products by
• Managing every requirement
• Understanding the link that each requirement has
  to every other decomposed requirement
• Managing the various lifecycle activities based
  on requirements
• Design based on requirements
• Unit/Functional/System Testing based on
  requirements
• Verification using either a spiral or V model as
  the case may be
• A requirement centric approach for the entire
  lifecycle

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Requirements Driven Development
Changemanagement
Configurationmanagement
Changemanagement

• Assess Impact

Requirementsmanagement
Design
Verification
Requirementsmanagement
Design

• Analyze

Definition
Implementation
Definition
Implementation

• Refine

• Build

Analysis
Analysis
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Requirements Driven Test
Testmanagement
Testmanagement
Changemanagement
Configurationmanagement
Changemanagement
Configurationmanagement

• Define

Requirementsmanagement
Design
Verification
Requirementsmanagement
Verification

• Plan

Definition
Implementation
Definition

• Execute

• Feed-back

Analysis
Test what was asked for, not simply what was
built!
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Visibility and Re-use across the lifecycle
Reuse diagrams/models
Requirementsmanagement
Simulate and verify
Analysis
Generate final application
Design
Implementation
Traceability
Increased efficiency with role based
approach shared information familiar
applications and user interfaces
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Ingredients for Organizing Requirements
Structure
Standard
Consistency
Domain Knowledge
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Definition of Traceability

• INFORMATION TRACEABILITY
• Understanding how information at a high-level is
  transformed into low-level.
• Understanding how needs are satisfied and
  qualified

• Principle underpinning
• Programme management
• Accountability
• Audit trails
• Risk management
• Safety management

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Example of Traceability
Keith Collyer This and the others like it should
be made consistent in appearance with the V-model
Design standards
Conforms to
Satisfies
Satisfies
Tests
Tests
Tests
Integration and Unit tests
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Steps to creating an Information Model

• An Information Modeling activity has many
  considerations
• Each and every user of the information
• Any and all processes impacted
• Data Elements of information (Requirements,
  Plans, change requests)
• Information structures and their attributes
• Needed views, reports and metrics
• Strategies for Tool integration and import/export
  of data
• Strategies for configuration/data management
• Ownership/User access rights

Identify
Four simple steps
Order
Relate
Create
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Identify all the different sources of information

• Everyone who creates, uses, reviews, benefits or
  otherwise has a stake in the use of the
  organizations Information Model
• These stakeholders often include
• Users
• Customers
• The Business
• Marketing
• Regulatory Representative
• System Engineering, Design, Test,
• Corporate Quality, Support and Maintenance
• Training, Documentation, Information specialists
• Functional Support Groups
• Other processes and tools

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Order by precedence and priority
Users
Customer
The Business
Every model differs in this regard. Often the
users and customers are at the top. Other
applications have the business as the main source.
r572
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Establish the relationships
Design Modules
Marketing
Users
System Requirements Document
Business
Test Cases
Customers
Roll-out Deployment Plan
Legal/ Regulatory
Quality/ Standards
Maintenance Manual
Training/ Support Documentation
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Build your Traceability Analysis
System requirements
User requirements
Architecture design
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Benefits of Requirements Driven Development

• The status of the project is never clear until we
  find weve missed project milestones
• We have very little formal development process
• We have a lot of standards to map to!
• Define the data and relationships and use
  requirements management disciplines to support
  process improvement
• Use traceability reports to show the degree of
  progress from one phase to another
• Use document templates to follow standards
• Pre-define project structures and reuse them for
  increasing efficiency and effectiveness

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Benefits of Requirements Driven Development

• The objectives always seem to change at the worst
  times
• Change is very costly and time consuming for us
• Requirements management shows the impact of a
  change before it is made
• Understand the consequences and cost of change
• Access controls prevent change at critical times
• Change management systems support change in a
  controlled way
• Build a system where your customers can
  participate
• When change is allowed, it is immediately
  accessible to the whole team,wherever they are

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Benefits of Requirements Driven Development

• We have difficulty communicating intent between
  departments
• We end up over-engineering our solutions which is
  costly
• Make requirements information readily accessible
  by all so that everyone is on the same page
• Give access to remote users via an
  Internet/Intranet connection
• Generate reports that allow easy verification
  that requirements have been decomposed correctly
• Obtain sign off from team members and customers
• Use traceability reports to ensure that all later
  phases genuinely flow back to original needs
• A quick report will show all design with no
  associated requirement

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Benefits of Requirements Driven Development

• We have trouble testing against original intent
  and stated need
• We are never sure whether our tests are full and
  complete
• Our test cycles are often too long and costly
• Traceability of tests back to original user
  requirements and business objectives ensures
  complete testing coverage
• Deriving tests directly from requirements results
  in meaningful tests
• Verification tables and orphan reports will show
  omissions
• Correct traceability from tests back to
  requirements can eliminate unnecessary testing
  and reduce test times
• Repeated failures can be quickly spotted and
  traced back to requirements for possible redesign

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Benefits of Requirements Driven Development

• Our customers often include design in the
  requirements
• We have difficulty organizing requirements into
  smaller manageable sets
• Proper data organization with different
  information types, all tracing back to the users
  need will help separate requirements from
  suggested design
• Design statements without clear associated
  requirements become easy to find with proper data
  organization
• By using a single requirements and traceability
  repository all requirements and related data can
  be kept in one place without resorting to huge
  documents
• Sorting a filtering requirements into manageable
  sets increases clear visualization and promotes
  efficiency

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Summary

• Requirements based Development provides extensive
  benefits to product development organizations
• Requirements drive the development
• Linking provides Traceability information and
  impact analysis
• Changing requirements can be managed effectively
• Changes to Standards (if any) can identify effort
  involved
• Quality is not compromised as requirements
  provide an extended interface to Compliance
• Reusability is possible

26
Thank you

• Team Telelogic
• NASSCOM
• v.k.kripanand_at_telelogic.com