SE

1. ESD.83 Cory R. A. Hallam 1
An Introduction to Systems Engineering
The Art of Managing Complexity
Presented By
Cory R. A. Hallam
B.Eng., M.Eng., ISU SSP, S.M.
October 16th, 2001, for ESD.83 at MIT

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Overview
• Systems Engineering has emerged as a distinct
professional discipline in direct response to the
increasing complexity of new development projects.
• We will review some of the reasons for the
emergence of this discipline and discuss the tools
and methodologies that have been established as a
means for dealing with increasing system complexity.

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Outline
• What is Systems Engineering?
• Emergence of the Discipline
• Role of the Systems Engineer
• The SE Process, Methodologies, and tools
• Setting standards
• SE, the ultimate solution?
• References

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What is Systems Engineering?
• It is not fundamental mathematics or strict laboratory
science
• It is a mix of HR, project management, business,
rational decomposition, trade studies, requirements
traceability, integration, testing, verification and
validation, operations, and end of life cycle disposal
of systems
• Standardizes the flow-down and traceability of
specifications for complex products from customer
requirements through production, operation , and
disposal

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What is Systems Engineering?
• Systems Engineering is an interdisciplinary approach
and means to enable the realization of successful
systems.
• It focuses on defining customer needs and required
functionality early in the development cycle, documenting
requirements, then proceeding with design synthesis and
system validation while considering the complete problem:
 Operations
 Performance
 Test
 Manufacturing
 Cost & Schedule
 Training & Support
 Disposal

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What is Systems Engineering?
• Systems Engineering integrates all of the disciplines
and specialty groups into a team effort forming a
structured development process that proceeds from
concept to production to operation.
• Systems Engineering considers both the business
and the technical needs of all customers with the goal
of providing a quality product that meets the user
needs

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Why has Systems Engineering
Emerged as A Distinct Discipline?
• The term itself was not
formally used, nor was the
importance of the concepts
recognized, until after World
War II.
• Complexity increased
orders of magnitude with the
creation of coupled mecho-
digital systems, especially in
defense (P-51 Mustang
versus the Trident in 10
years)
• Creation of systems of
systems, with users,
acquisition, training, service,
support, etc.
• Explosions = N!/2(N-2)!

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Emergence of Systems Engineering
Issues
• “The Mythical Man-month”, written by Fred Brooks,
who was the first manager of the OS/360
development team at IBM in the 1960's:
– People seem to think that people and time are
interchangeable and substitutable resources in projects
– Face it, the addition of people to a late project will only make
it later
– In computer systems, the issue of decomposition and
system management reared its ugly head with optimistic
programmers saying "This time it will surely run," or " I just
found the last bug."
– The false assumption is that things will take as long as they
“ought to take” and things will work as planned.
– Nothing works out as planned the first time - Systems
Engineering attempts to mitigate this issue

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The Role of the System Engineer
• Any engineer acts as a systems engineer when
responsible for the design and implementation of a
total system.
• The difference with “traditional engineering” lies
primarily in the greater emphasis on defining goals,
the creative generation of alternative designs, the
evaluation of alternative designs, and the
coordination and control of the diverse tasks that are
necessary to create a complex system.
• The role of Systems Engineer is one of Manager that
utilizes a structured value delivery process

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The Systems Engineering Process
• The major steps in the completion of a typical systems
engineering project are the following: (1) problem statement; (2)
identification of objectives; (3) generation of alternatives; (4)
analysis of these alternatives; (5) selection of one of them; (6)
creation of the system, and, finally, (7) operation.
• Some examples of Systems Engineering Process activities are:
• Defining needs, operational concept, and requirements
• Functional analysis, decomposition, and allocation
• System modeling, systems analysis, and tradeoff studies
• Requirements allocation, traceability, and control
• Prototyping, Integration, and Verification
• System Engineering Product and Process control
• Configuration and Data Management
• Risk Management approaches
• Engineering technical reviews and their purposes

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Systems Engineering Methodologies

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Systems Engineering Methodologies

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Managing Requirements
• Decomposition techniques create “chunks” that can
be handled by design teams and eventually individual
designers

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Who Sets the SE Standards?
• Depends on your
customer (MIL-
STD, IEEE STD,
Ad Hoc)
• Individual private
programs can be
managed in an
ad-hoc manner
• Government or
large corporate
contracts may
require Mil spec
or other spec to
ensure process
compliance
• INCOSE

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Tools
• Functional "thread" analysis involving use of
stimulus-condition-response threads for
specifications, development, testing, and reviews
• N-squared charts, QFD, Timeline analysis, and
Functional Flow Diagrams
• Activity Network Diagrams and professional quality
project and task schedules
• Object-oriented methodologies and distributed
networked IPDT’s

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Using Systems Engineering
Methodologies
• Some People think of SE tools and methodologies as
solution providers - plug in a bunch of “stuff” and get
THE answer, design, schedule, cost estimate,
etc…this is wrong.
• Systems Engineering provides a means for
discretizing systems problems into chunks that can
be solved, managed, and implemented - the
scheduling, costs, and interdisciplinary issues are
identified, but continuously change and emerge

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Is Systems Engineering the Solution to
all of the World’s Systems Problem?
NO...
... but it does help manage some of them

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Suggestions for Further Reading
• International Council on Systems Engineering
(INCOSE) web pages (2001), http:www.incose.org,
October 2001.
• Brooks, F., ( 1995 ). The Mythical Man Month:
Essays on Software
• Grady, Jeffrey O. (1994). System Integration, CRC
Press.
• QFD - Don Clausing
• Any new text on Systems Engineering