Transcript MSE607B Systems Engineering Module 1 Introduction to Systems Engineering

Engineering
Management
MSE607B
Systems Engineering
Module 1
Introduction to Systems Engineering
Introduction to Systems Engineering

Topics
• Importance of systems engineering in engineering
practice
• Subject of “systems” in general
• Origins of systems engineering
Learning Objectives

By the end of this module, you will be able to:
• Explain the need for creating systems and what
requirements they address
• Define some terms and characteristics of systems
• Evaluate systems based on their ability to fulfill specific
needs
• Discuss what activities management perform to
support the system engineering process
The Current Environment
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Requirements are constantly changing
Greater emphasis on total systems
Structures become more complex
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Life cycles of systems are extended; life cycles for
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technologies are shorter
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Utilize commercial off-the-shelf (COTS) equipment
Increasing globalization
Greater international competition
Increase in outsourcing
Decrease of available manufacturers
Higher overall life cycle costs
The Need for Systems Engineering
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System engineering addresses various needs to be
more effective and efficient in:
• Development and acquisition of new systems
• Operation and support of systems already in use
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Need to consider key concepts and definitions
Why Systems Engineering?
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Mars Climate Orbiter
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Lost in September 1999
Root cause of loss was failed
translation of English units
into metric units in a segment
of ground-based, navigationrelation mission software
"The problem here was not
the error, it was the failure of
NASA's systems engineering,
and the checks and balances
in our processes to detect the
error. That's why we lost the
spacecraft.“ – Dr. Edward
Weiler
Definition of System
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Generated from the Greek word systēma
• An “organized whole”
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Merriam-Webster Dictionary
• A regularly interacting or interdependent group of items
forming a unified whole
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Another definition
• Any set of interrelated components working together
with the common objective of fulfilling some
designated need
Additional Definitions
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International Council on Systems Engineering
(INCOSE)
• An interdisciplinary approach and means to enable the
realization of successful systems
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MIL-STD-499
• An interdisciplinary approach that encompasses the
entire technical effort to evolve and verify an integrated
and life cycle balanced set of people, products, and
process solutions that satisfy customer (stakeholder)
needs
Additional Definitions (cont.)
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General Characteristics
• Complex combination of resources
• Contained within some form of hierarchy
• May be broken down into subsystems and related
components
•
Allows for simpler approach and analysis of the system and
its functional requirements
• Must have a purpose
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Functional
Able to respond to identified need
Able to achieve its objective
Cost-effective
• Must respond to an identified functional need
Origins of Systems Engineering
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Foundation in the Natural and Physical Sciences
Driven by:
• Complex Systems
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Military, Space, Aerospace
• Longer Life Cycles
• Systems Failures
Origins of Systems Engineering
(cont.)
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Example: Transportation
System
• Physical Features
•
Main lanes, ramps,
connectors, and carpool lanes
• Operational controls
•
Speed limits, regulatory
restrictions, and management
controls
• All components must work
together to achieve the
common objective
Multiple Disciplines
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System Engineer
• Responsible for integration of multiple components into
one system
• Must have knowledge in:
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Mechanical
Electrical
Computer Science
Civil
Chemical Engineering
Cross-functional, multi-discipline engineers
Elements of a System
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Primary Components
• Physical objects, concepts, processes, feelings, and
beliefs
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System Boundary
• Encompasses components that can be directly
influenced or controlled
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Environment
• Factors that have influence on the effectiveness of a
system, but cannot be controlled
Elements of a System (cont.)
Example: Freeway System
Environment
System Boundary
Weather/Season
Vehicle
Characteristics
Origins/Destinations
Traffic Composition
Driving
Population
Access Roads
Operational Control
Enforcement
Guidance/Navigation
HOV
Main Lanes
Ramps and Connectors
Types of Systems
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Natural Systems
• Came into being through natural processes
• Examples: River System and Energy System
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Man-Made Systems
• Developed by human beings
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Physical and Conceptual Systems
Static and Dynamic Systems
Closed and Open-Loop Systems
Costs of New System Development
Cost
100%
80%
60%
Cost
Committed
Cost
Incurred
40%
20%
0%
Conceptual
Detailed
& Preliminary Design &
Design
Integration
Construction
or
Production
Use,
Refinement
& Disposal
Time
When Things Go Wrong
Easy to say “design was
bad”
 What is the “right” way to
do it?

• Most systems have to be
modified in order to ensure
better performance
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Systems engineering is
about learning from
experience
Three Laws of Systems Engineering
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Everything interacts with everything else
• Anything done to the system creates impacts that ripple
throughout the system
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Everything goes somewhere
• When working with a system, one deals with multiple
interfaces
• Account for interface and follow where it goes
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There is no such thing as a free lunch
• Everything comes at a price
Who Does Systems Engineering?
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Military/Govt Companies and Agencies
• Raytheon, Eaton, Parker, Boeing, Airbus, NASA
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International Council on Systems Engineering
(INCOSE)
• Non-profit membership organization founded in 1990
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International Centers for Telecommunication
Technology (ICTT)
• Specializes in solving its clients’ complex systems
problems
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All Companies and Engineers
Characteristics of a System
Engineer
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Big picture person
Focus on the objectives of the end user/stakeholder
Be able to take a broad perspective.
Leave nothing out and pay attention to details
Be able to consider and address all contingencies
A Mental Model for Systems
Engineering
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Systems engineering is like
peeling an onion
• Outer Layers
•
System description more abstract
and contains low level details
• Inner Layers
•
System description less abstract
and contains more design
requirements and elements
What Systems Engineers Do
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Key Foundations
• Systems Design
• Systems Analysis
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Tools and Methods
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Project Management
High Level Design
Planning, Modeling
Quality and Statistical
Analysis
Decision/Risk
Analysis
Simulation, Testing
Configuration Mgmt
Six Sigma, DFSS
Systems Engineering Process
Problem Definition
(planning)
Verification
(operations)
Systems
Approach
Mechanization
(construction)
Analytical Solution
(design)
Expertise on the Systems Team
Management
Domain/
Stakeholders
SE
Process
Technology
(Engineering
Disciplines)
Modeling,
Simulation,
Analysis
Key Terminology
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Life Cycle
Requirements
Functional vs. Physical
Qualification - Verification/Validation
The ‘Ilities’
Risk
System Life Cycle
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Includes entire spectrum of activity
• Identification of need through system design and
development
• Production and/or construction
• Operational use
• Sustaining maintenance and support
• System retirement
• Material disposal
System Life Cycle Stages
1.
2.
3.
4.
5.
6.
7.
Development
Manufacturing
Deployment
Training
Operations, maintenance, support
Refinement
Retirement
Autos – 5 to 10 Years
B-52 Bomber – 50 Years
Systems Failures
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Result from:
• Incorrect assumptions
• Oversights
• Mistakes
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Example
• Columbia Space Shuttle
• Miscalculated seriousness of
damage inflicted on isolation
panels of orbiter during lift off
Systems Failure Example:
Firestone Tires on Ford Explorer
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Low tire air pressure
175 deaths and 700 injuries
20 million tires replaced
Cost of $6 billion
Confluence of events in extreme conditions
Systems Failure Example:
Firestone Tires on Ford Explorer (cont.)
Failure Factor
Tread Notch Stress
Design
Operation
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Tire pressure
●
Temperature
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Repair of Punctures
Service
●
Rubber
Inflation Specification
Mfg
Years !!
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Systems Engineering Process:
“V” Model
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Development standard for IT systems of Federal
Republic of Germany
Standardizes activities and products in development
of IT systems
Guarantees
• Improvement in quality
• Curtailment of costs
• Improved communication between customers and
contractors
Systems Engineering Process:
“V” Model (Cont.)
UnderstandUser
Requirements,Develop
SystemConceptand
ValidationPlan
Dec
ExpandPerformance
Specifications intoCI
“Design - to”Specifications
and CIVerification Plan
n
iti o
p os
om
and ion
i nit
Def
Evolve“Design- to”
Specifications into
“Build - to”Documentation
andInspectionPlan
Time
AssembleCIs and
PerformCIVerification
toCI“Design - to”
Specifications
Inspect
“Build -to”
Documentation
Fab ,Assembleand
Codeto“Build -to”
Documentation
Right System?
rati
on
and
Qu
a l if
i cat
io n
. ..
. ..
Interfaces
Quality
Reliability
Usability
Producibility
IntegrateSystemand
PerformSystem
Verificationto
PerformanceSpecifications
DevelopSystem
PerformanceSpecification
andSystem
ValidationPlan
Models
Risk,
The Ilities
Demonstrateand
ValidateSystemto
UserValidationPlan
Int
eg
Requirements,
Documents,
Specifications
Built Right?
Systems Engineering
Design Engineering
How
Systems Engineering Process:
“Waterfall” Model (cont.)
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Software development model
 Standardized, documented
methodology
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Document system concept
Identify and analyze requirements
Break the system into pieces
Design each piece
Code the system components and
test individually
• Integrate the pieces and test the
system
• Deploy the system and operate it
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Widely used on large
Systems
Requirements
Software
Requirements
Preliminary
Design
Detailed
Design
Coding and
Debugging
Integration
and Testing
Operations and
Maintenance
Systems Engineering Process:
“Spiral” Model
Systems Engineering Process:
“Spiral” Model (Cont.)
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Advantages
• Estimates (budget
and schedule) get
more realistic as work
progresses.
• More able to cope
with the (nearly
inevitable) changes
that software
development
generally entails
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Disadvantages
• Estimates (budget
and schedule) are
harder at the outset
The Stakeholder
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Internal or external customer
Member of a group who will be involved with the
system
• Users, purchasers, maintainers, administrators
Relevant Stakeholder
• Describes people or roles designated in the
plan for stakeholder involvement
Requirements
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Key activity in system development
Define
• Needs and wants of the stakeholders
• What the system must do
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Condition or capability
• To solve a problem
• To satisfy a contract, standard, specification
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Most complex and crucial part in system
development
Bridge between application demands and solutions
Requirements (cont.)
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Four Categories
• Input/Output
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Interface between the system and other systems/components
• Technology/System Wide
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Technology being used throughout the system and its
components
• Trade Offs
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Solution options and the selections made
• Qualification
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What demonstrates compliance of the system to the
requirements
Requirements (cont.)
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Typical Requirements Analysis
• Identify source material
• Identify stakeholder needs
• Identify initial set of requirements (top-level functional,
non-functional, performance and interface
requirements)
• Establish design constraints
• Define effectiveness measures
• Capture issues/risks/decisions
Functional Models
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Transforms inputs into outputs
Describes what happens
• Problem defined by the requirements analysis in
clearer detail
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Identify and describe the desired functional behavior
of each system element or process
Typically performed without consideration of a
specific design solution
Functional Analysis
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Define operational scenarios
Derive system behavior model
• Reflect control and function sequencing, data flow and
input/output definition
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Derive functional and performance requirements
• Allocate to behavior model
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Define functional failure modes and effects
Interfaces
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Functions connect to other functions and systems via
interfaces
Standards of Interfaces
• Used in commercial applications
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System failures often occur at an interface
Architectures
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Gives the functionality,
connectivity, and structure
of the system
Used to identify the
interfaces
Provide the basis for the
system integration process
Operational
Concept
Functional
Architectur
e
Physical
Architectur
e
Operational
Architecture
Interface
Architecture
Qualification
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Demonstrates that system requirements have been
met
Covers the system requirements
• System/subsystem specifications
• Associated interface requirements specifications
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Verification of a system ensures that:
• Right system was built right
• Conformance to the system specifications
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Validation of a system ensures that:
• Right system was built
• Stakeholder acceptance
The “ilities”
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System design
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• Meets requirements
• Achieved desired
outcomes
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Reliability
Quality
Usability
Upgradeability
Flexibility
Manufacturability
Availability
Serviceability
Maintainability
Interoperability
Reliability
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Construction of a model that represents the times-tofailure of the entire system
• Based on the life distributions of the components from
which it is composed
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Example
• Expressed in terms of means hours between failure
• System Reliability is 500 hrs Mean Time Between
Failure (MTBF)
• If MTBF changes to 300 hrs, then:
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More spare parts needed
More service people needed
More service tools and space needed
Risk Analysis
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Analyzing and quantifying risk in:
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Technology
Experience, Knowledge base
Project Schedule
Project Budget
Undesirable events are identified and then analyzed
separately
For each undesirable event, possible improvements
are formulated
Summary
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Importance of systems engineering in engineering
practice
Subject of “systems” in general
Origins of systems engineering
Interactive Workshop
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A system is a:
a)
b)
c)
d)
Group of dependent but related elements
comprising a unified whole
Group of independent but interrelated elements
comprising a unified whole
Group of elements
Group of components
Interactive Workshop
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“Systems Engineering” is:
a) The process of defining, developing and integrating
quality systems.
b) The process of defining and developing quality
systems.
c) The application of engineering to solutions of a
complete problem
d) The set of activities controlling overall design and
integration of interacting components to meet the
needs of stakeholders.
Interactive Workshop
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Systems engineering requirements:
a)
b)
c)
d)
Stems from the Greek word requēma
Last activity in system development
Define the needs and wants of the stakeholders
Define the needs and wants of the engineers
Interactive Workshop
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A “life cycle” is the entire spectrum of activity:
a) From system design and development through
retirement and material disposal.
b) From system operations through retirement and
material disposal.
c) From system design through operation and material
disposal.
d) From system development through material disposal.
Interactive Workshop
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A “stakeholder” is a:
a) A person or group who studies systems
b) A member of a group involved with the system in
some way
c) A member of a group involved with Engineers in
some way
d) None of the above
Homework Assignment
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Page 44 problems
•
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•
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2
3
4
9
Use homework format provided in course
website
Read Chapter 2
• Pages 46-107
Questions? Comments?