1. Modeling and Analyzing
Non-Functional Requirements (NFRs)
to support
Architectural decision-making
SW Craftsmanship
May 14th, 2012
Daniel Gross, PhD
grossd@goalorientedsolutions.com
Daniel Gross © 2012

2. Talk Objective
• Illustrate that dealing with NFRs in projects is surprisingly
complex -- and modeling them can help discussing and
analyzing them
• Show that NFRs are key drivers that shape the software
system architecture
• Show that NFRs link between business goals and the
architecture – and that resolving NFR conflicts in organizations
may require business (commercial) decisions
• Examples from two industry case studies
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3. Architectural Decision Problem
Evolution path
planning
PBX/Call Control
Virtual
Intellig
Periph
From an industrial case study [14] ent tel.
eral
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[14] Gross, D. and E. Yu (2001). Evolving System Architecture to Meet Changing Business Goals: an Agent and Goal-Oriented Approach. Proceedings of the First International Workshop From Software Requirements
to Architectures (STRAW 2001) at the International Conference of Software Engineering. Toronto, Canada.

4. Decision-making in organizations
• Stakeholders (“the WML Team”) • NFRs of stakeholders
– Industrial designer – Seamless UI interaction
– Marketing – Portalization
– New Business Strategy – Ease of Use
– Desktop PLM – Cost of Phone set
– Architecture Strategy – Fast and easy access to key internet functions
– IP Phone architect – Increase mobility
– Call control Architect – Avoid unnecessary functionality
– Immediate access to functionality
– User Centric
– Quick addition of features
– Architectural evolution
– Reduce time to market
How to – Reduce new product risk
systematically deal – Maintain architectural integrity
with NFRs? – Maximize WML enabling of phone sets
– Reuse existing architectural solutions
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5. Intentional Actors show stakeholders goals
Stakeholder goals are visually
included inside Intentional Actors
(gray circles)
Actor
Actor Internal
View
Actors assigned to the
“WML” team.
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6. WML team in the organization
Goal delegation
Collective
actor type
Contribution link
Decision option
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7. NFR s as “soft” goals to Goal reasoning by the team
achieve
Refining NFRs into more
specific NFRs
Impact of solution
approaches on NFRs
Solution approaches
The architecture evolution problem?
Where in the architecture to place client browser
code, and why?
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8. Upper management
and their demands
At an
insurance
organization
Another “Team” and
its goal graph
One “Team” and its
goal graph Designer
Competing goal reasoning
between stakeholders
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9. !
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Product Management prioritizes goals
and hence resolves conflicting non-
functional demands on the SOA architect
and component designerGross © 2012
Daniel 9