Systems Engineering Described

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Systems Engineering

Described

12/28/09 Robert Johnson


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2009-1 2-29 SKF Slide 2 [Code]

SKF Sealing Solutions

Definition

Systems Engineering is:

A structured approach to the development of

complex, engineered systems.


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Components of Systems Engineering

The Whole System Approach

Project Management

The Iterative Design andEvaluation Method

Risk Management

Interface Design


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The Whole System Approach

Top-down design, optimizing for system effectiveness, not component

effectiveness.

E.g. Metallic structures on spacecraft can magnify radiation hazards. Metal

may be the best choice for the frame component, but may not be the bestchoice for the whole system.

Design the right system.

Systems design is inherently interdisciplinary. Systems Engineers must

possess and cultivate broad technical knowledge.

Manage subsystem interactions.


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Project Management

Manage cost, resource allocation, and scheduling constraints

from an engineering standpoint.

Collect the Voice of Customer (VOC), communicate with

stakeholders, and manage and coordinate suppliers.

Prepare and maintain a current Systems Engineering

Management Plan (SEMP) as the primary control document

for all system development activities.


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The Iterative Design and Evaluation Method

The Systems Engineering method is an iterative

process by which a system concept is developed

and refined, with continual evaluation againstrequirements, until a completed and functional

system design is produced that meets the goals

established for the system.


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The Iterative Design and Evaluation Method

1. Develop system performance and cost

requirements.

2. Develop multiple system concepts that can satisfy

most or all of the requirements.

3. Select a concept and begin the design / evaluation

loop.

4. Produce and implement the system.

Define

Concept

Design/Evaluate

Implement


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The Design / Evaluation Loop

At the outset of the design / evaluation loop, the system concept has

poor definition. Each pass through the loop increases the detail of the

design.

Also, at the outset there are many risks and unknowns. As detail is addedto the design, frequent evaluation of the design through testing and

simulation identifies problems that are then corrected in subsequent

design iterations. In this way risk is diminished on each pass through the

loop.

The design / evaluation loop concludes when a system design that

satisfies the performance and cost requirements is complete, and when all

risks relevant to the design have been abated or effectively managed.

EvaluateDesign


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Risk Management

Systems design carries large inherent risks relating to complexity and the

need to reach new levels of performance.

Some common systems risks are:

Interdependencies between subsystems magnify the effects of point failures.

Complex system behavior may be difficult to model or predict (greater than the sum of

its parts).

System dynamics are strongly characterized by bottlenecks, load variations, and

feedback loops.

New failure modes arise due to novel design, new technology, or increasing complexity.


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2009-1 2-29 SKF Slide 10 [Code]


Interface Design

The Systems Engineer (or team) is wholly responsible for the

specification and design of system interfaces.

Create and maintain current Interface Control Documents (ICDs) for all system

interfaces.

Interfaces carry material, information and energy between

components. Interface types include mechanical, electrical,

and data.

Interfaces are loaded junctions exposed to hazards from

more than one direction.


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2009-1 2-29 SKF Slide 11 [Code]


Interface Design (cont.)

Interfaces are sensitive to peak loads, and are

natural bottlenecks that can limit system

performance.Interfaces can be the source of unintended

feedback loops.

The more complex a system is the more criticalinterface design becomes.


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2009-1 2-29 SKF Slide 12 [Code]


Misconceptions About SystemsEngineering

Systems Engineering is a relatively new discipline, and not well-

understood in general industry, or in business. The term Systems

Engineer is often mistakenly applied to IT specialists. As has been

noted, Systems Engineers are generalists and not specialists of any

kind.

Systems Engineering was invented by the aerospace industry, and is

closely associated with it. However, Systems Engineering has broad

applications in manufacturing, civil engineering, business andenterprise management, public policy, and anywhere that a systems

approach can be valuable.


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2009-1 2-29 SKF Slide 13 [Code]


The Future of Systems Engineering

Systems Engineering is already being broadly applied to the redesign ofAmericas transportation and power generation networks, and similar

projects.

The application of principals of Systems Engineering outside of industrial

and civil applications is just starting to be investigated. One significantrecent development is the use of the Systems Engineering method in

Financial Engineering, currently under research at the University of

Illinois.

The use of Systems Engineering within Economics for the purpose of

designing effective public policies , and for engineering market-

effective solutions in business is a new field where research is just

beginning.

Systems Engineering Described

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