EuSEC Tool Vendors’ Challenge

Adie Ditchburn

Jon Chard

19 Sep 2006

2 © Telelogic AB

Approach

• Discuss Method of Deriving Requirements

– Structure

– Role of Modelling

• Relationship of Models to requirements

• Demonstrate DOORS Structure

– Database Level

– Module Level

• Demonstrate Modelling using TAU

– Use Case to System Level Activity Models

– Logical System Structure Models

• Discuss Information Traceability

• Demonstrate Traceability in DOORS

– Traceability Reports

3 © Telelogic AB

SystemRequirements

AgreeRequirements

QualificationStrategy

Analyze&

Model

StakeholderRequirements

AcceptanceStrategy

AgreeRequirements

SystemModels

AnalysisResults

DeriveRequirements& Qualification

Strategy

Deriving System Requirements

4 © Telelogic AB

Understanding your requirements

• Don’t just ‘list’ requirements, use structure to understand them

• Organise similar requirements into sections within documents

• Use structure to discover:

– Context (overall situation in which the requirement occurs)

• Allows you to see the “whole picture”

– Duplications (same requirement stated twice)

• Causes work to be performed twice

• Can lead to conflicting requirements

• Doubles your maintenance cost

– Omissions (missing requirements)

• Unstated requirements become missing functionality

• Could cause shortcomings in non-functional areas such as performance, reliability, ease of use - that can not be “re-engineered” back into the system once developed

5 © Telelogic AB

Functionalmodeling

Functionalmodeling

Functionalmodeling

Models Bridge Layers of Requirements

Requirements layer

Modeling layer

Requirements layer

Modeling layer

Requirements layer

Modeling layer

Requirements layer

e.g Goal / Usage modeling

e.g. Functionalmodeling

SponsorRequirements

DesignSpecification

SystemRequirements

Statementof need

e.g. Performancemodeling

Concept: Requirements and Modeling

6 © Telelogic AB

‘Tool Vendor Challenge’ CCC Layers of Requirements and Models

ChallengeStatement

Concept: Requirements and Modeling

Stakeholder Requirements

System Requirements

Sub-System Requirements

Constructed in DOORS

Functionalmodeling

Functionalmodeling

Functionalmodeling

Use Case modeling

Activitymodeling

Functionalmodeling

Constructed in TAU

Implementation

7 © Telelogic AB

DOORS and TAU Demonstrations

Demonstration of Requirements Structure in DOORS

Demonstration of SysML Modelling in TAU

Over to you Jon

8 © Telelogic AB

Requirements visualization and satisfaction through modelling in Tau with traceability to DOORS

9 © Telelogic AB

System black-box use cases in Tau SysML

10 © Telelogic AB

Example system block structure in Tau SysML

11 © Telelogic AB

Example configuration block internal structure diagram

12 © Telelogic AB

State machine description of subsystem block behaviour

13 © Telelogic AB

Information Traceability

• INFORMATION TRACEABILITY:

• Understanding how high-level objectives are transformed into low-level goals.

e.g. in business terms: Understanding how

• business vision interpreted

as• business objectives

implemented as

• business processes

e.g. in systems engineering:Understanding how• user requirements

satisfied by• system requirements

implemented as• design artifacts

implemented as• components

14 © Telelogic AB

Benefits of Information Traceability

• Greater confidencethat objectives are being met.

• Ability to manage changethrough ability to access change impact.

• Greater accountabilityof subordinate organisations/suppliers.

• Ability to track progress / statusparticularly in the formative stages of project.

• Ability to deliver valuethrough cost/benefit analysis.

15 © Telelogic AB

DOORS Demonstration

Demonstration of Production of Traceability Reports

Once again Jon

16 © Telelogic AB

Use of DOORS traceability analysis tools to show requirements satisfaction through SysML model.