Midterm Review Packet Stolen Borrowed from Prof. Marti Hearst. HFID Spring 2005. Affordances. The perceived properties of an object that determine how it can be used. Knobs are for turning. Buttons are for pushing. Some affordances are obvious, some learned Glass can be seen through.
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Midterm Review PacketStolen Borrowed from Prof. Marti Hearst
HFID Spring 2005
From McGrenere & Ho, Proc of Graphics Interfaces, 2000
Based on slide by Saul Greenberg
Based on slide by Saul Greenberg
Slide adapted from Saul Greenberg
full mapping
paired
arbitrary
front
back
front
back
backright
frontleft
backleft
frontright
2 possibilities per side
=4 total possibilities
24 possibilities, requires:
visible labels memory
Based on slide by Saul Greenberg
Based on slide by Saul Greenberg
Based on slide by Saul Greenberg
Based on slide by Saul Greenberg
Based on slide by Saul Greenberg
move
my.doc
Slide adapted from Saul Greenberg
Slide adapted from Saul Greenberg
Slide adapted from Saul Greenberg
Slide adapted from Saul Greenberg
Image from Newsweek, Jan 2001
Image from Newsweek, Jan 2001
Umm, thanks for the warning,
but what should I do?
What happens when you cancel a cancelled operation?
Do I have any choice in this?
Uhhh… I give up on this one
“HIT ANY KEY TO CONTINUE”
Slide adapted from Saul Greenberg
Kelly Goto & Eric Ott of Macromedia
http://www.gotomedia.com/macromedia/monterey/architecture/
From http://www.gotomedia.com/macromedia/monterey/architecture/
Slide adapted from Melody Ivory
Slide adapted from Melody Ivory
Adapted from slide by Dan Glaser
Slide adapted from Melody Ivory
Slide adapted from Melody Ivory
t sec.
KLMGOMS
(What Raskin refers to as GOMS)
Keystroke level model
1. Predict
2. Evaluate
x sec.
Action 1
Action 2
y sec.
Action 3
+
z sec.
Time using
interface 1
Time using
interface 2
Slide adapted from Newstetter & Martin, Georgia Tech
Raskin excludes
Symbols and values
Remarks
Time (s)
Operator
Press Key
Mouse Button Press
Point with Mouse
Home hand to and from keyboard
Drawing  domain dependent
Mentally prepare
Response from system  measure
0.2
.10/.20
1.1
0.4

1.35

K
B
P
H
D
M
R
Assumption: expert user
Slide adapted from Newstetter & Martin, Georgia Tech
0.2
.10/.20
1.1
0.4

1.35

K
B
P
H
D
M
R
Raskin’s rules
Rule 0: Initial insertion of candidate M’s
M before K
M before P iff P selects command
i.e. not when P points to arguments
Rule 1: Deletion of anticipated M’s
If an operator following an M is fully anticipated, delete that M.
e.g. when you point and click
Slide adapted from Newstetter & Martin, Georgia Tech
0.2
.10/.20
1.1
0.4

1.35

K
B
P
H
D
M
R
Raskin’s rules
Rule 2: Deletion of M’s within cognitive units
If a string of MK’s belongs to a cognitive unit, delete all M’s but the first.
e.g. 4564.23
Rule 3: Deletion of M’s before consecutive terminators
If a K is a redundant delimiter, delete the M before it.
e.g. )’
Slide adapted from Newstetter & Martin, Georgia Tech
0.2
.10/.20
1.1
0.4

1.35

K
B
P
H
D
M
R
Raskin’s rules
Rule 4: Deletion of M’s that are terminators of commands
If K is a delimiter that follows a constant string, delete the M in front of it.
Rule 5: Deletion of overlapped M’s
Do not count any M that overlaps an R.
Slide adapted from Newstetter & Martin, Georgia Tech
0.2
.10/.20
1.1
0.4

1.35

K
B
P
H
D
M
R
Example 1
Temperature Converter
Choose which conversion is desired, then type the temperature and press Enter.
Convert F to C.
Convert C to F.
Apply Rule 0
HPBHKKKKK
HMPMBHMKMKMKMKMK
Apply Rules 1 and 2
HMPBHMKKKKMK
Convert to numbers
.4+1.35+1.1+.20+.4+1.35+4(.2)+1.35+.2
=7.15
Slide adapted from Newstetter & Martin, Georgia Tech
0.2
.10/.20
1.1
0.4

1.35

K
B
P
H
D
M
R
Example 1
Temperature Converter
Choose which conversion is desired, then type the temperature and press Enter.
Convert F to C.
Convert C to F.
Apply Rule 0
HPBHKKKKK
HMPMBHMKMKMKMKMK
Apply Rules 1 and 2
HMPBHMKKKKMK
Convert to numbers
.4+1.35+1.1+.20+.4+1.35+4(.2)+1.35+.2
=7.15
Slide adapted from Newstetter & Martin, Georgia Tech
To convert temperatures,
Type in the numeric temperature,
Followed by C for Celcius or
F for Fahrenheit. The converted
Temperature will be displayed.
MKKKKMK = 3.7 sec
C
F
MKKKK = 2.15 sec
Slide adapted from Melody Ivory
Fitts’ Law
Models movement time for selection tasks
Slide adapted from Newstetter & Martin, Georgia Tech
Fitts’ Law
Time (in msec) = a + b log2(D/S+1)
where
a, b = constants (empirically derived)
D = distance
S = size
ID is Index of Difficulty = log2(D/S+1)
Slide adapted from Newstetter & Martin, Georgia Tech
Time = a + b log2(D/S+1)
Target 1
Target 2
Same ID → Same Difficulty
Slide adapted from Pourang Irani
Time = a + b log2(D/S+1)
Target 1
Target 2
Smaller ID → Easier
Slide adapted from Pourang Irani
Time = a + b log2(D/S+1)
Target 1
Target 2
Larger ID → Harder
Slide adapted from Pourang Irani
Slide adapted from Pourang Irani
Adapted from slide by James Landay
Interacting
Noninteracting
A1 A2
B135
B269
A1A2
B135
B268
B2
B2
B1
B1
A1
A2
A1
A2
A2
A2
A1
A1
B1
B2
B1
B2
Everyone uses both interfaces
Adapted from slide by James Landay
Studies involving human participants vs. measuring automated systems
High variability among people