Lecture 7: Systems Engineering

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Lecture 7 Systems Engineering
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Definition of a System

• A system is an interacting combination, at any
  level of complexity,
• of people, materials, tools, machines, software,
  facilities, and procedures
• designed to work together for some common purpose
  (Chapanis, 1996)

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Systems Engineering

• Systems -designed to meet user needs
• System development is iterative
• System development follows specs
• System engineering multi-disciplinary

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Elements of Systems
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Examples of Systems

• Production Systems
• systems for building and assembling products,
  e.g., computers and automobiles
• Transportation Systems
• e.g., automobiles, aircraft, ships, and
  railroads
• Information Processing Systems
• e.g., telephone systems, air-traffic control
  systems, automated bank tellers.
• Weapon Systems
• E.g., missiles, bombers, and tanks
• Service Systems
• E.g, police and fire systems, gas stations, and
  warehouses.

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The Space Shuttle
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Titan Rocket System Failure
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Military Systems
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Crowded Skies and Runways
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Making Systems Safer
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Nuclear Power
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Consequences of System Failure
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System Hierarchies
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The Role of People in Systems

• People are either inside or outside a system.
• e.g., orbiting satellite communication system
  must be maintained
• failure to consider human role can lead to unsafe
  or inefficient systems.
• People often bear ultimate responsibility for
  system operation.
• E.g, ship captain or aircraft pilot
• We can't sue automation, so people are ultimately
  responsible.
• Many accidents are attributed to human error.

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Types of Organization

• User Tool combinations
• E.g., a carpenter using a saw, a farmer using a
  rake, or a mechanic using a wrench
• Operator-Machine combinations
• an operator using a computer terminal, or a
  driver operating an automobile
• Multi-person systems
• E.g., banking systems, air-traffic-control
  systems, or postal systems

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Systems Engineering Team
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System Life Cycle
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Operational Need Determination

• Example of an Operational-Need Document
• The Fourth National Bank and Trust co.
• existing and Planned Operational Capabilities
• additional Operation Capability Required
• exploitable Technology
• constraints
• user Classes

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Operational Concept Formulation

• Example of an Operational Concept that satisfies
  the Operational Need for Automated Bank Tellers
• bank Customer Transaction Concept
• allowable Bank Customer Transactions
• allowable Number of Transactions
• logistics and Maintenance Concept
• management Concept
• training Concept

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Concept Exploration

• Major HF activities during concept exploration
• assist in allocation of functions
• conduct trade studies to evaluate costs and
  benefits of alternatives
• develop user-system interface requirements
• prototype and evaluate user interfaces

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Universal Access to ATM

• http//www.sun.com/access/wp-aatm/
• Japanese Tourist Visiting Canada
• Spanish Businessman with Low Vision
• Blind Student Making a Deposit

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Concept Demonstration

• Design concept is mocked up, simulated and
  tested.
• Does it meet
• requirements for staffing, operating,
  maintaining, and supporting the system?
• dimensional requirements for workspace, etc.,
• safety, personnel and training requirements

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Full Scale Engineering Development

• Full prototype is developed and tested.
• Prototype includes all necessary hardware and
  software
• Major HF tasks
• Usability testing with product and documentation
• Reference of testing results to performance
  requirements

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Production and Deployment

• Multiple copies of system are produced and
  distributed
• Major HF tasks
• training operators and users on system
• evaluating usability or operability of system
• identifying changes to be made for later versions

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Operation and Maintenance

• Systems delivered and in use
• Major HF tasks
• conduct follow-on tests of operator satisfaction
  with use and maintenance of system
• results of tests serve as guides to engineering
  changes for subsequent versions

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System Retirement

• In this phase the system is retired from use,
  scrapped or replaced
• Concerns about environmental conversation and
  recycling of materials
• Ease and expense of disposal should be considered
  during system design

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Life Cycle Control Points

• There are control points throughout the system
  lifecycle
• Control points are milestones times at which
  evaluations are made
• Evaluations consist of reviews and audits
• System engineer describes what has been done and
  defends activities

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Questions asked at Control Points

• Is the work - to date- satisfactory?
• Do any changes need to be made in the
  development?
• Are the budgets and timetables for completion
  realistic?