2004 Midterm review

1
Tutorial 5

• 2004 Midterm review
• SY DE 142 June 21, 2004
• Introduction to Human Systems Engineering
• Waterloo, Ontario, Canada

2
Q1.a

• A. people will pay 8.2 cents per pound more for
  beef that is 90 lean than for beef that is 10
  fat. What specific kind of cognitive bias is this
  an example of .
• A framing bias. This was discussed in class and
  announced as guaranteed midterm question.(1 mark)

3
Q1.b

• b. Studies have shown that people who use
  gestures when they talk may communicate more
  effectively that people who dont use gestures.
  Explain how Multiple Resource Theory might
  predict this result.
• Multiple resource theory says that people have
  different pools of resources that they can attend
  to, e.g. an auditory pool and a visual pool.
  These pools have different resource limits.
  According to multiple resource theory you should
  be able to increase capacity or performance by
  putting additional information on to the other
  pool. Since gestures are visual and speech is
  auditory, they use different pools. This may
  allow more communication transfer. (3 marks 1
  for understanding that the different resources
  are sense related and in this case were tapping
  auditory and visual, 1 for being very clear that
  it is the listener who is doing the information
  processing, 1 for the idea of increasing capacity
  by using 2 different resource pools or clearly
  stating that using 2 pools the person processes
  more information)
• Not accepted more efficient too vague, explain
  how, added redundancy you can add redundancy on
  the same channel and not increase the
  information, being more interesting this may be
  true but doesnt use MRT

4
Q2

• A worker cleaning an auxiliary building at a
  power plant catches his shirt on a breaker. In
  pulling it free, he activates the breaker,
  shutting off current to the control rods in the
  reactor. The reactor shut down automatically and
  it took 4 days to bring it up again. Explain why
  this is an accident caused by system
  characteristics.
• It is a system accident because
• an unexpected interaction occurred (you could
  also say nonlinear)
• a small change caused a large change in the
  reactor (indicating the system was tightly
  coupled)
• Marking This would be a two mark question with
  one mark for each point. This example was used in
  the lecture in class.

5
Q3

• Mary sends out this message I am writing a
  midterm today in two different ways, once using
  Morse Code, and then using email. (Morse code is
  way of communicating that has only two keys, dash
  and dot, and alphabet letters are made by
  combinations of three dashes or dots. Assume
  Mary is very proficient at both Morse code and
  typing. Which method will she likely send out
  the message the fastest? Why? Which method will
  she have the fastest keystroke/second speed?
  Why?
• Total message will be faster typing due the
  Decision Complexity Advantage. because more
  information is being sent per keystroke. I was
  picky and wanted the specific law named as well
  as the explanation for 1 mark.
• Keystroke speed will be faster with Morse Code
  because of the Hick Hyman law. The HH law states
  that decision speed is faster with fewer
  decisions to be made, in this case, 2 keys rather
  than 26. Again state the law.
• Not accepted Fitts law. There is no information
  on target width or distance to target (amplitude)
  so you really cant solve this problem with Fitts
  law.

6
Q4

• Use Action Cycle to explain what happened in the
  case study the Lost Cord.
•  Goal monitor girls condition
• Intention monitor her heart using the EKG
  machine
• Sequence of Actions tape electrodes to girls
  chest , run lead across mattress, plug into heart
  monitor machine
• Actions physically doing the above sequence but
  plugs into IV pump instead
• World Girl connected to IV pump and electricity
  into girl.
• Perception seeing girl get electrocuted
• Interpretation wrong amount of electricity into
  girl, wrong piece of equipment.
• Evaluation could not monitor girls condition ,
  girl dead goal not achieved ( you need to tie
  back to goal)
• (½ mark for labels and ½ mark for explanation)

7
Q5.a

• In Set Phasers on Stun, is there a gulf of
  evaluation? And why?
• There is no information on the state of the world
  , there is no information to perceive, there is
  no information to evaluate.
• (3 marks for 3 reasons) You are expected to use
  the human action cycle directly.

8
Q5.b

• Propose one solution in each category
• making an error reversible , making an error
  visible and making an error impossible
• Reversible Allow Mary Beth to look at her entry
  and revise it before starting treatment
• Visible Warning that the set level may be too
  high
• Impossible Prevent the device from emitting
  fatal levels of radiation under all
  circumstances.
• (there may be some other solutions here)

9
Q6

• Bob is in his final year of high school. He is
  interested in 2 universities and is trying to
  decide which one to go to. The universities
  differ on certain attributes. Use
  Multi-attribute utility theory to determine which
  university Bob should go to.
• Attribute Utility of the U1 score U2 score
  Attribute
• Social life 10 2 8
• Reputation 3 10 3
• Closeness 5 3 7
• to home
• Sports teams 9 4 5
• Quality 7 8 4
• SCORE 157 197
• U12103105394782030153656 157
• U2 81033755947809354528197 Bob
  should go to U2.
• Marks 2 for the correct method (2 for the correct
  scores, 1 for the correct decision.

10
Q7

• Explain what Automation Complacency is.
  Describe its effect on human operators. Give an
  example of automation complacency from the film
  Why Planes Crash.
• From the notes, automation complacency refers to
  a situation where operators overtrust the
  automation. (1 mark)
• They fail to monitor it vigilantly enough and
• become less aware of the state of the system
• they are slower to detect problems
• and less able to intervene in a problem
  (de-skilling) (4 marks)
• An example from the film is when the pilots focus
  on the burned out lightbulb. They assume the
  plane is in autopilot and stop monitoring the
  altitude. By the time they realize the plane has
  descended too much they are unable to intervene.
  (2 marks)
• Or the example of aircraft shut down as flying on
  autopilot, pilots not aware they entered Russian
  No-Fly zone
• Or, Chinese aircraft on autopilot, pilots not
  aware of engine failure.

11
Q8 Solve the Human Factors Crossword Puzzle (10
marks 1 per word)

• Across
• 4. error with correct intention and wrong
  action slip
• 5. bias related to how a question is
  posed framing
• 7. an interface design approach for complex
  systems EID (Ecological Interface Design)
  .25 for ECO.
• 8. perception of elements, their meaning, and
  projection of future states situation
  awareness
• 9. type of processing used to resolve ambiguous
  information top down
• Down
• 1. when people overtrust automation they become
  this complacent
• 2. approximate number of items kept in short term
  memory seven
• 3. law relating response time to number of
  choices Hick Hyman
• 5. law relating movement time, target size and
  distance Fitts
• 6. error with wrong intention Mistake