Module 1 Introduction to Systems Engineering

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Module 1Introduction to Systems Engineering
MSE607BSystems Engineering
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Introduction to Systems Engineering

• Topics
• Importance of systems engineering in engineering
  practice
• Subject of systems in general
• Origins of systems engineering

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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

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The Current Environment

• Requirements are constantly changing
• Greater emphasis on total systems
• Structures become more complex
• Life cycles of systems are extended life cycles
  for technologies are shorter
• Utilize commercial off-the-shelf (COTS) equipment
• Increasing globalization
• Greater international competition
• Increase in outsourcing
• Decrease of available manufacturers
• Higher overall life cycle costs

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The Need for Systems Engineering

• 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
• Need to consider key concepts and definitions

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Why Systems Engineering?

• Mars Climate Orbiter
• Lost in September 1999
• Root cause of loss was failed translation of
  English units into metric units in a segment of
  ground-based, navigation-relation 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

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Definition of System

• Generated from the Greek word systema
• An organized whole
• Merriam-Webster Dictionary
• A regularly interacting or interdependent group
  of items forming a unified whole
• Another definition
• Any set of interrelated components working
  together with the common objective of fulfilling
  some designated need

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Additional Definitions

• International Council on Systems Engineering
  (INCOSE)
• An interdisciplinary approach and means to enable
  the realization of successful systems
• 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

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Additional Definitions (cont.)

• 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
• Functional
• Able to respond to identified need
• Able to achieve its objective
• Cost-effective
• Must respond to an identified functional need

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Origins of Systems Engineering

• Foundation in the Natural and Physical Sciences
• Driven by
• Complex Systems
• Military, Space, Aerospace
• Longer Life Cycles
• Systems Failures

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Origins of Systems Engineering (cont.)

• 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

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Multiple Disciplines

• System Engineer
• Responsible for integration of multiple
  components into one system
• Must have knowledge in
• Mechanical
• Electrical
• Computer Science
• Civil
• Chemical Engineering
• Cross-functional, multi-discipline engineers

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Elements of a System

• Primary Components
• Physical objects, concepts, processes, feelings,
  and beliefs
• System Boundary
• Encompasses components that can be directly
  influenced or controlled
• Environment
• Factors that have influence on the effectiveness
  of a system, but cannot be controlled

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Elements of a System (cont.)
Example Freeway System

• Environment

System Boundary
Weather/Season
Access Roads
Vehicle Characteristics
Guidance/Navigation
Operational Control
Origins/Destinations
HOV
Main Lanes
Enforcement
Traffic Composition
Ramps and Connectors
Driving Population
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Types of Systems

• Natural Systems
• Came into being through natural processes
• Examples River System and Energy System
• Man-Made Systems
• Developed by human beings
• Physical and Conceptual Systems
• Static and Dynamic Systems
• Closed and Open-Loop Systems

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Costs of New System Development
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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
• Systems engineering is about learning from
  experience

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Three Laws of Systems Engineering

• Everything interacts with everything else
• Anything done to the system creates impacts that
  ripple throughout the system
• Everything goes somewhere
• When working with a system, one deals with
  multiple interfaces
• Account for interface and follow where it goes
• There is no such thing as a free lunch
• Everything comes at a price

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Who Does Systems Engineering?

• Military/Govt Companies and Agencies
• Raytheon, Eaton, Parker, Boeing, Airbus, NASA
• International Council on Systems Engineering
  (INCOSE)
• Non-profit membership organization founded in
  1990
• International Centers for Telecommunication
  Technology (ICTT)
• Specializes in solving its clients complex
  systems problems
• All Companies and Engineers

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Characteristics of a System Engineer

• 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

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A Mental Model for Systems Engineering

• 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

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What Systems Engineers Do

• Key Foundations
• Systems Design
• Systems Analysis

• Tools and Methods
• Project Management
• High Level Design
• Planning, Modeling
• Quality and Statistical Analysis
• Decision/Risk Analysis
• Simulation, Testing
• Configuration Mgmt
• Six Sigma, DFSS

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Systems Engineering Process
Mechanization (construction)
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Expertise on the Systems Team
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Key Terminology

• Life Cycle
• Requirements
• Functional vs. Physical
• Qualification - Verification/Validation
• The Ilities
• Risk

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System Life Cycle

• 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

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System Life Cycle Stages

1. Development
2. Manufacturing
3. Deployment
4. Training
5. Operations, maintenance, support
6. Refinement
7. Retirement

Autos 5 to 10 Years
B-52 Bomber 50 Years
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Systems Failures

• Result from
• Incorrect assumptions
• Oversights
• Mistakes
• Example
• Columbia Space Shuttle
• Miscalculated seriousness of damage inflicted on
  isolation panels of orbiter during lift off

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Systems Failure Example Firestone Tires on Ford
Explorer

• Low tire air pressure
• 175 deaths and 700 injuries
• 20 million tires replaced
• Cost of 6 billion
• Confluence of events in extreme conditions

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Systems Failure Example Firestone Tires on Ford
Explorer (cont.)
Failure Factor Design Mfg Operation Service
Tread Notch Stress ?
Rubber ?
Inflation Specification ?
Tire pressure ?
Temperature ?
Repair of Punctures ?
Years !!
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Systems Engineering Process V Model

• 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

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Systems Engineering Process V Model (Cont.)
Requirements, Documents, Specifications
Right System?
Models
Interfaces
Built Right?
Risk, The Ilities
Quality Reliability Usability Producibility
How
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Systems Engineering Process Waterfall Model
(cont.)

• Software development model
• Standardized, documented methodology
• 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
• Widely used on large government systems

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Systems Engineering Process Spiral Model
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Systems Engineering Process Spiral Model
(Cont.)

• 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

• Disadvantages
• Estimates (budget and schedule) are harder at the
  outset

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The Stakeholder

• 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

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Requirements

• Key activity in system development
• Define
• Needs and wants of the stakeholders
• What the system must do
• Condition or capability
• To solve a problem
• To satisfy a contract, standard, specification
• Most complex and crucial part in system
  development
• Bridge between application demands and solutions

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Requirements (cont.)

• Four Categories
• Input/Output
• Interface between the system and other
  systems/components
• Technology/System Wide
• Technology being used throughout the system and
  its components
• Trade Offs
• Solution options and the selections made
• Qualification
• What demonstrates compliance of the system to the
  requirements

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Requirements (cont.)

• 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

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Functional Models

• Transforms inputs into outputs
• Describes what happens
• Problem defined by the requirements analysis in
  clearer detail
• Identify and describe the desired functional
  behavior of each system element or process
• Typically performed without consideration of a
  specific design solution

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Functional Analysis

• Define operational scenarios
• Derive system behavior model
• Reflect control and function sequencing, data
  flow and input/output definition
• Derive functional and performance requirements
• Allocate to behavior model
• Define functional failure modes and effects

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Interfaces

• Functions connect to other functions and systems
  via interfaces
• Standards of Interfaces
• Used in commercial applications
• System failures often occur at an interface

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Architectures
Operational Concept

• Gives the functionality, connectivity, and
  structure of the system
• Used to identify the interfaces
• Provide the basis for the system integration
  process

Functional Architecture
Physical Architecture
Operational Architecture
Interface Architecture
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Qualification

• Demonstrates that system requirements have been
  met
• Covers the system requirements
• System/subsystem specifications
• Associated interface requirements specifications
• Verification of a system ensures that
• Right system was built right
• Conformance to the system specifications
• Validation of a system ensures that
• Right system was built
• Stakeholder acceptance

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The ilities

• System design
• Meets requirements
• Achieved desired outcomes

• Reliability
• Quality
• Usability
• Upgradeability
• Flexibility
• Manufacturability
• Availability
• Serviceability
• Maintainability
• Interoperability

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Reliability

• Construction of a model that represents the
  times-to-failure of the entire system
• Based on the life distributions of the components
  from which it is composed
• 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
• More spare parts needed
• More service people needed
• More service tools and space needed

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Risk Analysis

• Analyzing and quantifying risk in
• Technology
• Experience, Knowledge base
• Project Schedule
• Project Budget
• Undesirable events are identified and then
  analyzed separately
• For each undesirable event, possible improvements
  are formulated

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Summary

• Importance of systems engineering in engineering
  practice
• Subject of systems in general
• Origins of systems engineering

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Interactive Workshop

• A system is a
• 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

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Interactive Workshop

• Systems Engineering is
• The process of defining, developing and
  integrating quality systems.
• The process of defining and developing quality
  systems.
• The application of engineering to solutions of a
  complete problem
• The set of activities controlling overall design
  and integration of interacting components to meet
  the needs of stakeholders.

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Interactive Workshop

• Systems engineering requirements
• Stems from the Greek word requema
• Last activity in system development
• Define the needs and wants of the stakeholders
• Define the needs and wants of the engineers

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Interactive Workshop

• A life cycle is the entire spectrum of
  activity
• From system design and development through
  retirement and material disposal.
• From system operations through retirement and
  material disposal.
• From system design through operation and material
  disposal.
• From system development through material disposal.

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Interactive Workshop

• A stakeholder is a
• A person or group who studies systems
• A member of a group involved with the system in
  some way
• A member of a group involved with Engineers in
  some way
• None of the above

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Homework Assignment

• Page 44 problems
• 2
• 3
• 4
• 9
• Use homework format provided in course website
• Read Chapter 2
• Pages 46-107

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Questions? Comments?