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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