visualizing the impact of non-functional requirements on...

Centre de Rechercheen Informatique

REV’08 / Session 3

REV'08: Third International Workshop on Requirements Engineering VisualizationMonday 8th September

Barcelona, Spain

Visualizing the Impact ofNon-Functional Requirements

on Variants – A Case Study

Clotilde [email protected]





[email protected] Page 1

The problem:

Current visualization techniques lack convenience and do notprovide sufficient clarity about impact of non-functionalrequirements on variants.

The importance:

Many developers must address NFRs.

e.g. Teamcenter software non-functional requirements arerepresented as Items and are the criteria for setting views of theProduct Structure (performance view and the security view).





The problem:

The NFRs are

dispatched

everywhere

in the figure






Who is the visualization for?

Every stakeholders that has to deal with non-functionalrequirements and their impact on variants:

• From the vendor side: technical sales support, benchmarker,developers, prototypers, project leaders, implementators etc.

• From the customer side: managers, project leaders, users,etc.



What is the visualization for?

The visualization should support the work of stakeholders in eachbusiness and product lifecycle management steps when one has todeal with non-functional requirements and their impact on variants:

• Benchmark (incl. Prototype)

• Process Accessment

• Specification

• Implementation

• Testing and Validation

• Change Management Process





We propose a visualization that expects to helpto see at first glance:

- the Non-Functional Requirements (NFRs)

- the Functional Requirements

- the Impact of NFRs on variants








Variants Panel

Quality Requirements Panel

Impact of NFRson Variants PanelFunctional Requirements

Non-Functional Requirements

1

2

3



Functional Requirements



Gi

a

Sij

b

1

Gj

Map model [Rolland 2000, Rolland et al. 2007]





Variants PanelFunctional Requirements

Gi

a

Sij

b

1

Gj

Variants arebased on mapmodel.



Gi

a

Sij

b

1

Gj

MAP graphicalrepresentation of a section

Atomic Variant

Why variant representation based on MAP model?

The visualization supports all variant types:optional variants, alternatives, mandatory, iterative.





Map sections linked by a bundlerelationship

Simple Variant withAlternate Choice

Map sections linked by a multi-thread relationship

Simple Variant with MultipleChoice





Map sections linked by a pathrelationship

Path Composite Variant





Sij1Sjk

a b11

2

3

Sij2

Sij3

Gi Gj

Gk

c

Sik

1

Map sections linked by amulti-path relationship Multi-Path Composite Variant





NFR Visualization

Using the representation of [Chung et al., 1996]

Decomposition of NFR goal Performance/Time into one or two sub-goals






Impact of NFRs on Variants Panel

Correlation links, adopted from [Chung et al., 2000]

--

- ? + ++

BREAK HURT UNKNOWN HELP MAKE





Impact of NFRs on Variants Panel

Layer 1: Impact of NFRs on atomic variants

Layer 2: Impact of NFRs on

simple and composite variants



• NFRs Impact on atomic variants

<NFR Impact value on atomic variant>

Variant Vi





Maprel.

Representation of thecorresponding variant

Visualization of NFRImpact on variant

None





Multi-Threadrelation-ship

Bundlerelation-ship





Maprelationship


Visualization of NFR Impacton variant

Pathrelationship





Maprelationship


Visualization of NFR Impacton variant

Multi-pathrelationship





Summary Graphical Representation on NFR Impact on Simple & Composite Variants







NFR’s testing and ISO compliance

No NFR Test Scenario Example ISOCompliance

1 SuitabilityThe capability of the

test object toprovide anappropriate set offunctions forspecified tasks

and user objects.

Execution ofinstructions andfunction blocks,transfer of data, timeresponse.

Transfer ofbytespersecond

Yes

Example



Scalability of the representation:

The scalability is enabled by• 1) the decomposition method of the map for the functional

requirements and• 2) the typology of NFR according to the Chung NFR types or

ISO9126.

As requirements become more complex, one can keep therepresentation uncluttered by showing a map of the highest level.The user may view details by traversing the hierarchy of maps.

Also, rather than viewing a total representation, the user can viewNFRs according to their NFR types. For example, one could viewfirst the NFR decomposed goals of performance and then the NFRdecomposed goals of user-friendliness or security.





The case studyThe visualization has been used in practice for validating the work

This study addressed software for reporting Product LifecycleManagement (http://www.siemens.com/plm )





Map of data reporting tool for Product Lifecycle Management




Where used information

Where referenced informationBOM informationWorkflow information

Master informationetc.



Variants Panel


Impact of NFRson Variants Panel







• Evaluation

All variabilityrepresentationtypes

Type ofexpressedvariability

Variant type according our approach

A l t e r n a t i v ebundles

Simple Variant with multiple choiceMulti-path Composite Variant

Alternatives Simple Variant with Alternate Choice

Options Optional Variant like Simple Variant withmultiple Choice or Path Composite Variant orMulti-path Composite Variant or atomicVariant which belongs to a Path CompositeVariant

O p t i o n a lAlternatives

Optional Variant like Simple Variant withAlternate Choice belonging to a PathComposite Variant





Evaluation- Dependencies- NFRs representation- Clarity





The results



This visualization approach clarifies use of variantcombinations based on non-functional requirements.One can navigate through the variants and getinformation about the quality attributes according tothe approach.

Applying our approach, we obtained preliminarydesign views for the reporting tool that wereimplemented in the resulting reporting system.Leaders who participated in this case studyresponded positively.



Thanks for your attention!



Questions?

visualizing the impact of non-functional requirements on...

Documents