Traceability

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Traceability

• James D. Palmer

Presented by Megan Heffernan
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Agenda

• What is traceability?
• Why is traceability important?
• How is traceability performed?
• What tools perform traceability?
• What is the future of traceability?

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Introduction

• What makes a software project successful?
• Meets stakeholder requirements
• How can this be encouraged?
• Traceability
• Traceability in a nutshell
• Shows forward and backward relationships linking
  requirements with design, implementation, test,
  and maintenance
• Know reasoning for everything and how to test

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Why is Traceability Important?

• Ensures that requirements are met
• Understand relationship between requirements and
  the delivered system
• Lowers risk
• Creates an audit trail
• Consistency
• Control
• Change
• Development
• Risk

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Problems with Traceability

• Manual process
• Viewed by developers as a low priority
• Misunderstood
• No single modeling method
• Poor documentation

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When Does Traceability Occur?

• Entire lifecycle!

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How is Tracing Performed?

• Client gives developers rough requirements
• Developers create system, hardware, and software
  requirements
• Each element is given a unique identifier
• Element requirement, design attribute, test,
  etc
• Linkages done manually and managed by a CASE tool
• Traceability tables are made
• Matrix

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Traceability Example

• SRD System Requirements Document
• High level requirements
• Done by stakeholders
• SS System Specification
• More detailed requirements
• Developer interpretation
• Segments
• More detailed portions of the SS
• Includes design information

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Traceability Example
System Requirements Document
System Specification
Interface Control Document
Segment 1
Segment 2
Segment 3
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Traceability Example

• Traceability Matrix

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Traceability Management

• Requirements are added/deleted/modified
• Impact analysis
• Trace changed
• Continues through maintenance

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Traceability in a Perfect World

• Steps
• Identification of requirements
• Architecture selection
• Classification schema
• Functions, Performance and Security
• Translate into views
• Allocation into schemas
• Flow-down to design, code, and test
• Entry into traceability database
• Linkages
• Management

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Traceability in the Real World

• Labor Intensive
• Classification schemas are frequently changed as
  requirements are allocated
• Ensure that semantics and syntax are correct

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Semantics and Syntax

• Semantics required to assure that a trace is used
  in context
• Syntax required to assure that a trace goes to a
  specific word or phrase
• Manual verification of outcomes

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Real World Traceability Workflow

• Receipt of requirements documents
• Select architecture form to be followed
• Select classification schema
• Parse document and assign unique numbers
• Allocate according to classification scheme
• Establish linkages across all requirements
• Generate traceability matrices
• Maintain traceability linkages in database
• Maintain traceability links across entire project

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Return on Investment

• Very difficult to measure
• Many factors
• Costs
• Time
• CASE Tools
• Training
• Benefits
• ???
• Only an estimation
• What rework was avoided?

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Tools

• CASE Tools
• Characteristics
• Hypertext linking
• Unique identifiers
• Syntactical similarity coefficients
• Problems
• Hypertext linking and syntactical similarity does
  not consider context
• Unique identifiers do not show requirement
  information
• Choosing architecture view and classification
  schemas will always be manual

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Tools

• DOORS
• Telelogic
• capture, link, trace, and manage
• For large applications
• From the datasheet
• Similar look and feel to explorer
• Gap analysis for unaddressed requirements
• Traceability analysis for identifying areas of
  risk
• Impact analysis reports
• Volatility
• Traceability by drag and drop

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DOORS
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DOORS
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Tools

• Caliber-RM
• Borland
• From the datasheet
• Centralized repository
• Requirements traceability across the lifecycle
• Impact analysis

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CaliberRM
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CaliberRM
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Future Predictions

• Automation of allocation into architectures and
  classification schemas
• Little additional automation seen in current
  tools
• AIRES (Automated Integrated Requirements
  Engineering System)
• Center for Software Systems Engineering at George
  Mason University
• Relies heavily of semantics and syntax

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Pros/Cons

• Pros
• Clearly reflected traceability importance and
  need
• Practical workflow
• Cons
• Examples did not reflect lifecycle
• Little practicality with tools

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Agenda Revisited

• What is traceability?
• Why is traceability important?
• How is traceability performed?
• What tools perform traceability?
• What is the future of traceability?

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Questions?