IS1042
Human Information Processing
Summer I 2006

Assignments

Assignments: You will see that sometimes the assignments preceed the chapter, in order to give you some experience with the issues before we discuss them, and sometimes they will follow the discussions in order to give you practice with the ideas we have discussed. Some problems will require only brief answers and others will take some time. All assignments are strictly individual. All assignments should be sent to is1042dm@sis.pitt.edu If an assignment involves graphs that you find difficult to draw using software you may submit a paper copy. Make sure that it is neat and reflects the care that you put into the work. All assignments are due by 2:00 on the day indicated.

• Assignment for May 24:
  1. Assume a 4 row by 6 column array of off-on cells in a visual sensing device such as the retina, labelled as follows: the 6 cells in row 1 are a1...a6, the 6 cells in row 2 are b1...b6 etc. Show how these 24 cells would be connected to detect the following "features":
     1. the four horizontal lines
     2. the six vertical lines
     3. a moving horizontal line going up the field
     4. a moving vertical line going left to right
     5. all of the horizontal lines of length 4, in the first two rows
     6. the six vertical lines going from the bottom of the field to the second row
     7. all of the angles consisting of a vertical line that ends at a four cell horizontal line that begins at that point (that is, this detects angles, not T's)
        
        
     Use the following notation:
     
     
     • Rather than trying to draw all the connections as lines, use a series of "equations" to show which cells are connected to which. The equations should have a left hand side consisting of all the cells feeding into a higher level cell, and a right hand side consisting of the cell they are feeding into.
     • Instead of an = sign, use a => to mean an immediate connection or a /=> to mean a time delayed connection.
     • Use the labels I indicated above for the original on-off cells, i.e., a1 through d6.
     • label the "feature detectors" as follows:
       • four horizontal lines: h1...h4
       • six vertical lines: v1...v6
       • moving horizontal line going up the field: mh
       • moving vertical line going left to right: mv
       • all of the horizontal lines of length 4, in the first two rows: sh4-a1 (short horizontal length4 starting in cell a1), each of these will vary only in the cell that it starts from.
       • the six vertical lines going from the bottom of the field to the second row: sv-1 (short vertical in row 1)
       • the angles consisting of a vertical line that ends at a four cell horizontal line that begins at that point: a-a1 (angle from cell a1)
       So for instance, the equation for the first row full horizontal line is:
       a1 a2 a3 a4 a5 a6 => h1
       Label your work clearly and show the equations in the order described above.

       All of this may look complex at first but it really isn't difficult. See me if you have trouble understanding the instructions.

     
     
  2. Consider the following issues in system design/human factors/human computer interaction. Choose any three and for each, find a study (or studies) in chapter 3 that relates to that issue and describe what can be understood from that study in relation to the issue (e.g., what can we learn about how to build systems, displays etc. or how can we address that issue). Try to be as specific and plausible as you can.
     
     
     1. The design of "heads up" displays (i.e., displays shown on the windsheilds of planes and cars) and what kind of information should be shown on them or what needs to be considered in building such displays.
     2. The design of a black and white display that is intended to show an unusual object among a large set of other objects (e.g., a military plane among a large set of civilian aircraft).
     3. You are resposible for developing an auditory alerting system for jet pilots. Someone suggests that each message ought to be stated in English in a calm voice so that the pilot isn't distracted from what s/he is doing.
     4. You are at a CIA meeting where someone suggests that a spy could be inserted at an enemy meeting to try to view certain documents that will be on display and try to memorize them. The choice of covers for the spy is between a stenographer who will have to type everything said at the meeting, or a participant at the meeting who will have to discuss the issues with other participants.
  
  
• Assignment for June 5:
  
  
  1. Show a propositional representation of the following sentence a. as a list of the propositions in linear notation and b. as a propositional network graph.
     
     

     	The smart students solved the hard problem.
     

     
     
  2. Describe a small semantic network (about 10 classes and 10 features) of some of the categories under the concept "transportation vehicle".
  3. Describe a script for going to a doctor. How much of that script can be abstracted into a script for visiting a prefessional? Show a small semantic network consisting of the scripts for professional, medical professional, and doctor.
  
  
• Assignment for June 14:
  
  
  1. Write a set of rules (in English/pseudocode) encoding the knowledge that a person would use to add two three digit numbers. This is a problem decomposition problem in which the top level goal is broken into subgoals, and these are broken into subgoals until finally a step that can be immediately taken is reached. So you should have rules of the following types:
     1. If the goal is to do X (and optionally, condition(s) Y hold) then create subgoal to do Z (and perhaps additional subgoals)
     2. If the goal is to do X (and optionally, condition(s) Y hold) then do Z (where Z is a simple action that doesn't require subgoals) and mark X as done
     3. If goals X1...Xn are marked done then mark goal Y as done (where X1...Xn are the suboals created to accomplish goal Y)

     The idea is to break complex operations such as "add two three digit numbers" into simpler operations until you reach a level at which actions can be immediately taken. For this problem we can consider the level at which you are adding two or three single digits the level at which actions can be immediately taken. Here are examples of the three types of rules:

     1. If the goal is to add two three digit numbers and the first column hasn't been added then create the goal of adding the first column
     2. If the goal is to add the first column then add the two digits in that column and place the ones digit in the ones place of the answer and the tens digit in the carry of the second column and mark the goal of adding the first column as solved.
     3. If the goal to add the first column and the goal to add the second column and the goal to add the third column and the goal to add the fourth column* are solved than the goal to add the two three digit numbers is solved.
     
     
  2. Imagine a search space with a branching factor of 3 and a uniform depth of 5 (where the initial node is considered to be at level 1, and assume that the only goal node in the space is the second from the left of the fifth level. How many nodes would each of the following search strategies explore before finding the goal?
     1. depth-first
     2. breadth-first
     3. hill-climbing with a perfect heuristic evaluation function
  
  
• Assignment for June 23 3:00 PM:
  
  
  1. Give your own real world examples of situations that exhibit: base-rate neglect, subjective utility, framing effects.
  2. Show the phrase structures for two interpretations of:
     The man saw the tree on the hill with a telescope.
  3. Describe five principles or suggestions from the field of cognitive psychology that can help students learn more effectively.