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Introduction to engineering


Introduction to engineering Dr. Yan Liu Department of Biomedical, Industrial and Human Factors Engineering Wright State University * User-Centered Design (UCD) Eight ... – PowerPoint PPT presentation

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Title: Introduction to engineering

Introduction to engineering
  • Dr. Yan Liu
  • Department of Biomedical, Industrial and Human
    Factors Engineering
  • Wright State University

Engineering Versus Science
  • Scientists
  • Understand why our world behaves the way it does
    (laws of nature)
  • Study the world as it is
  • Thinkers
  • Engineers
  • Apply established scientific theories and
    principles to develop cost-effective solutions to
    practical problems
  • Cost effective
  • Consideration of design trade-offs (esp. resource
  • Minimize negative impacts (e.g. environmental and
    social cost)
  • Practical problems
  • Problems that matter to people
  • Change the world
  • Doers

ABETs Definition of Engineering
  • ABET (The Accreditation Board for Engineering and
    Technology )
  • Recognized in the United States as the sole
    agency responsible for accreditation of
    educational programs leading to degrees in
  • Engineering is the profession in which a
    knowledge of the mathematical and natural
    sciences, gained by study, experience, and
    practice, is applied with judgment to develop
    ways to utilize, economically, the materials and
    forces of nature for the benefit of humankind

Engineering Disciplines
  • Major Disciplines
  • Mechanical engineering
  • Electrical engineering
  • Civil engineering
  • Chemical engineering
  • Industrial engineering
  • Computer engineering
  • A subspecialty within electrical engineering at
    many institutions
  • Specialized, Non-Traditional Fields
  • Aerospace engineering
  • Materials engineering
  • Biomedical engineering
  • Nuclear engineering
  • etc.

Electrical/Computer Engineering (ECE)
  • Largest of All Engineering Disciplines
  • About 353,000 or 26 (out of 1.4 million
    engineers) were electrical and computer engineers
    (U.S. Department of Labor Statistics in 2005)
  • Concerned with electrical devices and systems and
    with the use of electrical energy
  • Specialties
  • Electronics
  • Design of circuits and electric devices to
    produce, process, and detect electrical signals
  • Communications
  • A broad spectrum of applications from consumer
    entertainment to military radar

Electrical/Computer Engineering (ECE)
  • Specialties (Cont.)
  • Power
  • Generation, transmission, and distribution of
    electric power
  • Conventional generation systems (e.g.
    hydroelectric, steam, and nuclear)
  • Alternative generation systems (e.g. solar, wind,
    fuel cells)
  • Controls
  • Design of systems that control automated
    operations and processes
  • Instrumentation
  • Use of electronic devices to measure parameters
    (e.g. pressure, temperature, flow rate, speed,
  • Processing, storing, and transmitting the
    collected data

Mechanical Engineering
  • Second Largest Engineering Discipline
  • About 221,000 or 16 (out of 1.4 million
    engineers) were mechanical engineers (U.S.
    Department of Labor Statistics in 2005)
  • Concerned with designing tools, engines,
    machines, and other mechanical equipment
  • Areas
  • Energy
  • Production and transfer of energy and conversion
    of energy from one form to another
  • Structures and motion in mechanical systems
  • Design of transportation vehicles, manufacturing
    machines, office machines, etc.
  • Manufacturing
  • Design and build requisite equipment and tools to
    convert raw materials into final products

Industrial Engineering
  • Industrial Engineering is concerned with the
    design, improvement, and installation of
    integrated systems of people, material,
    information, equipment, and energy. It draws upon
    specialized knowledge and skill in the
    mathematical, physical, and social sciences
    together with the principles and methods of
    engineering analysis and design to specify,
    predict, and evaluate the results to be obtained
    from such systems (IIE (Institution of
    Industrial Engineering), 1985)
  • Also known as systems engineering, production
    engineering, operations management
  • Fields
  • Operations research
  • Human factors
  • Quality control
  • etc.

Industrial Engineering
  • Operations Research
  • Uses methods like mathematical modeling,
    statistics, and algorithms to arrive at optimal
    or good decisions in complex problems
  • Human Factors (or Ergonomics)
  • Application of scientific information concerning
    humans to the design of objects, systems and
    environment for human use (IEA (International
    Ergonomics Association), 2007)
  • Physical human factors
  • Deals with the human body's responses to physical
    and physiological stress
  • Cognitive human factors
  • Mental processes (e.g. perception, attention,
    cognition, motor control, and memory storage and
    retrieval) as they affect interactions among
    humans and other elements of a system
  • Organizational human factors (macroergonomics)
  • The optimization of socio-technical systems,
    including their organizational structures,
    policies, and processes

Industrial Engineering
  • Quality Control
  • Ensure products or services are designed and
    produced to meet or exceed customer requirements
  • Similarity to Other Engineering Disciplines
  • Trained in the same basic ways as other engineers
  • Take foundation courses in mathematics, physics,
    chemistry, humanities, and social sciences
  • Difference from Other Engineering Disciplines
  • Emphasis on both people and technology
  • Focuses on how people interact with a system
  • Concern for the human element leads to system
    designs that enhance the quality of life for all

  • Wikipedia Definition
  • Process of originating and developing a plan for
    a product, structure, system, or component
  • Achieve Goals with Constraints
  • Goals
  • The purposes of the design
  • What is for? Who is it for? Why do they want it?
  • Constraints
  • Material, cost, time, regulation, etc.
  • Trade-off
  • Which goals or constraints can be relaxed so that
    others can be met
  • Understand the Material

A chair with a steel frame and a chair with a
wooden frame are quite different. Often the steel
frames are tabular or thin L or H section steel,
whereas wooden chairs have thick solid legs.
Why? What would happen if a wooden chair were
made using the design for a metal one and vice
To design a system that involves humans, we have
to understand humans, their physiological,
psychological and social aspects and how they
interact with the other components of the system
Bad Design (1)
Whats wrong with the design of this knife?
Although you can tell which end is the handle and
which end is the blade, it isn't clear which side
of the blade cuts
Bad Design (2)
Whats wrong with the design of this stove?
It is difficult to tell which control goes with
which burner
Good design Arrange the controls in the same
configuration as the burners. It is quite easy to
tell which burner goes with which control
Bad Design (3)
Whats wrong with the design of this Boombox?
People generally expect the controls for a device
to be on or close to the device. In this example,
the CD buttons should be put next to the CD
player and the tape buttons should be put next to
the tape player.
Good Design (1)
Fun, educational, self-explanatory
LeapFrog's "Twist and shout multiplication"
Good Design (2)
Simple, elegant, easy to use, easy to clean
How to Make Good Design
  • Recognize that systems are built for users and
    thus must be designed for the users
  • Recognize individual differences
  • Recognize that the design of things and
    procedures can influence human behavior and
  • Emphasize empirical data evaluation
  • Rely on scientific method
  • Recognize that things, procedures, environments,
    and people do not exist in isolation

What Is NOT Good Design
  • NOT just applying checklists and guidelines
  • These can help, but user-centered design (UCD) is
    a design philosophy and process
  • NOT using oneself as the model user
  • Know your real users recognize variation in
  • NOT just common sense
  • e.g. a picture is worth a thousand words does
    not always hold

QWERTY Keyboard
  • Layout
  • QWERTY are first six letters at the top row of
    alphabetical keys
  • The layout of the digits and letters is generally
    fixed except a few variations in some nations
  • e.g. French keyboards interchange both "Q" and
    "W" with "A" and "Z", and move "M" to the right
    of "L"
  • Non-alphanumeric keys vary
  • e.g. There is a difference between key
    assignments on British and American keyboards
  • Above 2 and 3 on the UK keyboard are the ltgt and
    ltgt, respectively, whereas lt_at_gt and ltgt are on the
    USA keyboard
  • The placement of brackets, backslashes and such
    like vary
  • Not optimal for typing

French keyboard
US keyboard
UK keyboard
Dvorak Keyboard
  • An alternative standard keyboard layout to
    QWERTY, patented in 1936 by August Dvorak and
    William Dealey
  • Designed to address the problems of inefficiency
    and fatigue that characterized the QWERTY
    keyboard layout
  • Speed improvement of 10 15
  • Reduction in user fatigue due to the increased
    ergonomic layout of the keyboard
  • Has failed to replace QWERTY standard
  • Currently, all major operating systems (e.g.
    Apple OS X, Microsoft Windows, GNU/Linux) can
    ship the Dvorak keyboard layout in addition to
    the QWERTY layout

Dvorak Keyboard
  • Ergonomics Principles of the Design
  • It is easier to type letters alternating between
  • For maximum speed and efficiency, the most common
    letters should be the easiest to type. This means
    that they should be on the home row, the center
    row of alphabetical letters on a keyboard, which
    is where the fingers rest and under the strongest
  • The least common letters should be on the bottom
    row, which is the hardest row to reach
  • The right hand should do more of the typing,
    because most people are right-handed
  • Stroking should generally move from the edges of
    the board to the middle. An observation of this
    principle is that, for many people, when tapping
    fingers on a table, it is easier going from
    little finger to index than vice versa

Dvorak Keyboard Layout
Chord Keyboard
  • Only a few keys are used
  • Allow users to enter characters or commands
    formed by pressing several keys together, like
    playing a chord on a piano (illustration)
  • Advantages
  • Extremely compact and thus can be built into a
    device (e.g. a pocket-sized computer) that is too
    small to contain a normal sized keyboard
  • A large number of combinations available from a
    small number of keys allows text or commands to
    be entered with one hand, leaving the other hand
    free to do something else
  • Disadvantages
  • Lack of familiarity
  • Cannot be used by a "hunt and peck" method, so
    their use is restricted to applications where
    additional training can be justified
  • Hunt and peck typing (or two-fingered typing) is
    a common form of typing, in which the typist must
    find and press each key individually

  • 12 keys, so more than 4000 combinations are
    potentially possible
  • User can set up key combinations as macros for
    longer strings of text

Twiddler2 Developed by Handykey Corp.
  • Concerned with making systems easy to learn and
  • A Usable System is
  • Easy to learn
  • Easy to remember how to use
  • Effective to use
  • Efficient to use
  • Safe to use
  • Enjoyable to use
  • Why is Usability Important
  • Many everyday systems and products seem to be
    designed with little regard to usability, which
    leads to frustration, wasted time and errors

Examples of interactive products mobile phone,
computer, personal organizer, remote control,
soft drink machine, coffee machine, ATM, ticket
machine, library information system, the web,
photocopier, watch, printer, stereo, calculator,
videogame etc.
The photocopier in our college has buttons like
these on its control panels
Imagine that you just put your document into the
photocopier and set the photocopier to make 10
copies, sorted and stapled. Then you push the big
button with the "C" to start making your copies.
What do you think will happen? (a) The
photocopier makes the copies correctly. (b) The
photocopier settings are cleared and no copies
are made
If you selected (b) you are right! The "C" stands
for clear, not copy. The copy button is actually
the button on the left with the "line in a
diamond" symbol. This symbol is widely used on
photocopiers, but is of little help to someone
who is unfamiliar with this.
  • Important Design Principles of Usability (Norman,
  • Visibility
  • All necessary controls should be visible for the
    user whenever he/she is supposed to be able to
    use them
  • The design should provide visibility to all the
    set of possible actions
  • One control for each action that the user can
  • Only the necessary parts should be made visible,
    depending upon the actions available to the user
  • Much visibility is harmful since it makes the
    system look complicated to use
  • Affordance
  • The affordance of an object refers to the sort of
    operations and manipulations that can be done to
    the object
  • There should be a natural mapping between the
    parts that are made visible and the actions that
    they support
  • e.g. A button, by being slightly raised above an
    otherwise flat surface, suggests the idea of
    pushing it

  • Important Design Principles of Usability (Norman,
  • Feedback
  • Sending back to the user information about what
    action has actually been done and what results
    have been accomplished
  • Feedback should be provided in a form that is
    easy to understand and interpret
  • Accommodation of errors
  • Minimize the chance of the error in the first
    place or its effects once it occurs
  • Make sure that the users have the right
    conceptual model of the system
  • Make it hard for users to commit a mistake
  • Forcing functions can be introduced to prevent
    errors from occurring by providing strong
    constraints on the system
  • a) Interlock that maintains a task sequence
  • b) Lockin that prevents premature termination
    of a task sequence
  • c) Lockout that prevents starting a faulty
  • Allow the users to reverse the results of an
    error or to recover the state of the system

User-Centered Design (UCD)
  • What is UCD
  • UCD a design philosophy and a process in which
    the needs, wants, and limitations of the end user
    of a product are given extensive attention at
    each stage of the design process
  • A multi-stage problem solving process which
    requires designers to not only analyze and
    foresee how users are likely to use a product but
    also test the validity of their assumptions with
    regards to user behavior in real world tests with
    actual users

User-Centered Design (UCD)
The UCD Cycle in ISO13407 (Four activities
interlock and form the basis for an iterative
approach to the requirements-design-test cycle
the cycle is completed when the evaluation of a
product shows that it meets the specified
User-Centered Design (UCD)
  • Eight Steps in UCD
  • Step 1 Define the context
  • Step 2 Describe the user
  • Step 3 Task analysis
  • Step 4 Function allocation
  • Step 5 Basic design
  • Step 6 Mockups prototypes
  • Step 7 Usability testing
  • Step 8 Iterative test redesign

User-Centered Design (UCD)
  • Define the Context
  • Identifying the type of applications or the usage
    of the system
  • e.g. Develop a kiosk for a zoo to provide
    practical information (e.g. how to get from
    location A to location B) as well as content to
    enrich the experience
  • Market
  • Whether this is a need for the system to justify
    its development
  • Describe the User
  • The important characteristics of the users of the
  • Physical attributes (e.g. age, gender, size,
    reach, etc.)
  • Perceptual abilities (e.g. vision, hearing,
    touch, etc.)
  • Cognitive abilities (e.g. memory span, reading
    level, expertise level, etc.)
  • Personal traits (e.g. likes/dislikes,
    extrovert/introvert, patience, etc.)
  • Cultural and international diversity (e.g.
    languages, culture, ethics, etc.)
  • Special population (e.g. disabilities, elders,
    minors, etc.)

User-Centered Design (UCD)
  • Task Analysis
  • Analyzing the way users perform the tasks when
    using the system
  • Talk to and observe users doing what they do
  • List each task
  • Break tasks down into steps
  • Function Allocation
  • Decide who or what is best suited to perform each
    task (or each step)
  • e.g. Machine remembers login Id and reminds the
    user, but the user remembers the password
  • Base this on knowledge of system hardware,
    software, users abilities, culture,
    communications protocols, privacy, cost, etc.

User-Centered Design (UCD)
  • Basic Design
  • Summary of the components and their basic design
    (be creative!)
  • Brainstorming
  • Cross-check with design requirements, human
    factors references, hardware specifications,
    budgets, laws/regulations, etc.
  • Ensure that the design will support the
    requirements and comply with the constraints
    (verification and validation in software
  • Mockups Prototypes
  • Rapidly mock up the system for testing with
    potential users
  • Pen and paper or whiteboard to start
  • Iterate, iterate, iterate!!
  • Increasingly functional and veridical
  • Implement a detailed prototype of the system
  • Prototyping is the process of quickly putting
    together a working model of the system in order
    to test various aspects of its design
  • Various prototyping tools are available
  • Visual Basic/Visual Basic.NET, Flash,
    Dreamweaver, Caretta, Synopsis, etc.

User-Centered Design (UCD)
  • Usability Testing
  • Get real (or representative) users to perform
    tasks, using the prototype
  • Both objective and subjective (e.g. satisfaction)
  • Sometimes users want features that actually
    yield poor performance
  • Testing results are used to guide the iterative
    evaluation and redesign of the system
  • Iterative test redesign
  • Repeat cycles of testing and reworking the
    system, subject to cost/time constraints
  • Focus on Functionality First !

  • An effective technique for generating a large
    number of ideas in a group setting
  • At least 2 people, but no more than 10 people
  • Facilitator
  • Guide the session, encourage participation, write
    down ideas, etc.
  • Facilities
  • A brainstorming space
  • Something to write down ideas (e.g. paper,
    white-board, etc.)
  • Four Rules
  • Rule out criticism
  • Welcome freewheeling
  • Seek large quantities of ideas
  • Encourage combination and improvement of ideas

  • Types of Brainstorming
  • Free-form (unstructured) brainstorming
  • Participants simply contribute ideas as they come
    to mind
  • Pros
  • Participants can build on each others ideas
  • Relaxed atmosphere
  • Cons the less assertive or low-ranking
    participants may not contribute
  • Structured brainstorming
  • Solicit one idea from each person in sequence
  • Pros
  • Each person has an equal chance to participate,
    regardless of rank or personality
  • Cons
  • Lack of spontaneity
  • Rigid environment
  • Combination of free-form and structured

Design Touch Screen Zoo Information Kiosk
  • 1. Define the Context
  • Identifying the type of applications or the
    usage of the system
  • Benefits to justify its development

Design Touch Screen Zoo Information Kiosk
  • 2. Describe the User
  • The important characteristics of the users of
    the system
  • Physical attributes
  • Age a wide range (16 70)
  • Size and reach 5th percentile 95th percentile
    of American population in the age of 16 to 70
  • Perceptual attributes
  • Vision normal
  • Touch normal
  • Cognitive attributes
  • Reading level Understanding of English at a high
    enough level to recognize and follow on-screen
  • Culture and international diversity
  • Language English

Design Touch Screen Zoo Information Kiosk
3. Task Analysis
Design Touch Screen Zoo Information Kiosk
4. Function Allocation
  • User makes selections on the touch screen, and
    the machine processes the commands

5. Design
Main Screen
Idle Screen
Design Touch Screen Zoo Information Kiosk
5. Design (Cont.)
Animal Info Screen
Zoo Information Screen
6. Mockup Prototype
Design Touch Screen Zoo Information Kiosk
7. Usability Evaluation
  • Thirteen people who have been to zoos
    participated in the usability evaluation
  • Each participant performed a set of tasks
    (predetermined by the experimenters) on the
    prototyped design, and their task performance,
    including the number of clicks and number of
    errors, was recorded
  • After the tasks, each participant filled out a
    subjective questionnaire to rate his/her
    satisfaction with different features of the
  • Evaluation data was analyzed

8. Iterative Test Redesign
  • Based on the evaluation outcome, plans to
    improve the design were made