Hardware/Software Integration in System-of-Systems Architecting: The Role of Systems Modeling...
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Transcript of Hardware/Software Integration in System-of-Systems Architecting: The Role of Systems Modeling...
Hardware/Software Integration
in System-of-Systems
Architecting:
The Role of Systems Modeling
University of Southern California
Viterbi School of Engineering
Systems Architecture & Engineering (SAE)
Ken CuretonMarch 15, 2006
[email protected]@boeing.com
3/15/2006 SOS HW-SW Integration.ppt
Page 2
System-of-Systems Modeling
• A Key Challenge in Systems-of-Systems Architecting:– To describe a complex system rigorously and
unambiguously– Such that the integrated system design can be
tested and verified to meet requirements• Before
generatingany code
• Beforedesigninganyhardware
THE GLOBALINFORMATIONGRID (GIG)
3/15/2006 SOS HW-SW Integration.ppt
Page 3
System-of-Systems Modeling
• Other Goals in Describing a Complex System Rigorously and Unambiguously:– Serve as a means of describing the system design
to customers– Serve as a guiding path for completing the
hardware and software design according to plan– Serve as a constant reference for measuring
progress during the design process– Detect/correct any divergence from the approved
system design– Such that the impact of inevitable design
problems are minimized
3/15/2006 SOS HW-SW Integration.ppt
Page 4
System-of-Systems Modeling
• The Reality of Systems Architecting:– There WILL be design problems!– And WHEN they occur… be detected and resolved as
early as possible in the detailed design process:• Design holes or “OSIF’s”
(Oh Shucks, I Forgot)• Unexpected interfaces, dependencies, and
couplings• “Unk-Unk’s” (unknown-unknowns)
– Unrealistic goal:• Minimize number of design changes
– More practical goal:• Accomplish a large portion of necessary design
changes in the Conceptual Design Phase• More/better “experimentation” may be
beneficial?
3/15/2006 SOS HW-SW Integration.ppt
Page 5
System-of-Systems Modeling
CO
ST
IM
PA
CT
DESIGN PROTOTYPE DEPLOYCONCEPT
DE
SIG
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LE
XIB
ILIT
Y
X10
X10
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IMPACT OF DESIGN CHANGESDURING A SYSTEM’S LIFE CYCLE
SOURCE: Design For Competitiveness Concurrent Engineering Handbook© 1992 by Bart Huthwaite, Institute For Competitive Design
3/15/2006 SOS HW-SW Integration.ppt
Page 6
System-of-Systems Modeling
• What is the Root Cause of Most Design Changes?– A study by the US General Accounting Office
showed a 4% probability of success in delivering software
• At cost and on schedule
• That actually met customer needs
– “Well, that’s what I TOLD you to do,but that’s not what I NEED you to do…”
– A 1975 study showed that a majority of software errors in delivered systems are not coding related
• Instead, they are a direct result of missing, conflicting, mis-understood, or mis-interpreted requirements
3/15/2006 SOS HW-SW Integration.ppt
Page 7
System-of-Systems Modeling
• A Few Personal Observations Regarding Design Changes:– People tend to work on the EXCITING things first
• Necessity of tangible evidence to support proposals?– “Hard” problems are too often left until the end
• More useful focus would be to tackle design challenges in priority by RISK
– Hardware choices are often “assumed” based on prior system experience, results of Research & Development, and presumed customer preferences
– All too often, the “hard” problems are left to the software developers• Who are further constrained by hardware choices
– Another key goal of the System Architect:• Accomplish the “correct” HW/SW partitioning early in
the design process, with buy-in from all stakeholders and consideration of all life cycle phases
3/15/2006 SOS HW-SW Integration.ppt
Page 8
System-of-Systems Modeling
• SysML v1.0a: One Candidate Tool to Accomplish Modeling Goals
SOURCE: http://www.sysml.org/Copyright © 2003-2006 SysML Partners
3/15/2006 SOS HW-SW Integration.ppt
Page 9
System-of-Systems Modeling
• “Executable” SysML Models– Modeled System-of-Systems can be run, tested,
debugged, and measured for performance
– Allows “execution” tovalidate the systemdesign over its life cycle
• Initially at a top level
• Increasing levels offidelity as the designmatures or is updated
THE GIG ENTERPRISESERVICES (GES)
3/15/2006 SOS HW-SW Integration.ppt
Page 10
System-of-Systems Modeling
• Is Model-Driven Architecture (MDA)“The Answer?”– Separates specification of system functionality from
specification of implementation on a specific technology platform
– Structured around some set of specific concepts
• Or is Domain-Driven Architecture (DDA)More Useful? Domain-Driven Design Premise:– Key to development is knowledge of subject matter
and finding useful ways of understanding that subject matter
– Focus on complexity of the domain itself• Not the technical architecture• Not the user interface• Not even specific features
3/15/2006 SOS HW-SW Integration.ppt
Page 11
System-of-Systems Modeling
• A Few Predictions For The Future:– The “Methods Wars” aren’t really over yet…
– The US Government will likely require detailed architecture models with all proposals
• With the goal of using them to contrast/compare proposed system performance, interoperability in a System-of-Systems, and assess Life-Cycle Risk(Cost, Schedule, and Performance)
• Witness the potential impact of the Federal Enterprise Architecture (FEA):
3/15/2006 SOS HW-SW Integration.ppt
Page 12
System-of-Systems Modeling
• The Federal Enterprise Architecture (FEA):
3/15/2006 SOS HW-SW Integration.ppt
Page 13
System-of-Systems Modeling
• For Any Complex, Comprehensive System,the System Architect Needs:– Ability to validate requirements
(i.e. ensure having the “right” requirements)– Ability to communicate a common vision
to many different people and organizations– Ability to iterate the conceptual design process to
reduce risk in subsequent states of the system’s life cycle
– Ability to contrast, compare and integrate system elements from multiple sources• Large & small, internal and external
– Ability to verify that delivered elements will smoothly integrate into the system
System-of-Systems Modeling May Bea Useful Tool in Achieving These Goals
System-of-Systems Modeling May Bea Useful Tool in Achieving These Goals