CS228 HumanComputer Interaction

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CS228 Human-Computer Interaction
Design as Philosophy Design as Process
Design is an attempt to translate
a need or desired function into a physical
structure or process in the best way possibl
e.
What is meant by best? (Design philosophy)
How should the translation be carried out?
(Design process) Design philosophy and process
differs across domains Aesthetic design Art
istic design Visual design Architectural desig
n Grammatical design Technical design Physi
cal design Software design Interface design
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CS228 Human-Computer Interaction
Aesthetic design
Q What are the principles of beauty?
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CS228 Human-Computer Interaction
Visual design
Q What are the principles of communicating
information visually?
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CS228 Human-Computer Interaction
Architectural design
Straddles artistic and technical design
Buildings must be beautiful, but also
functional. Introduces constraints not every bui
lding is
inhabitable.
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CS228 Human-Computer Interaction
Engineering design
Converge on set of functional requirements
first The system should do X Design Princ
iples Separate functions within the artifact
A wheel should allow for smooth transport over
flat terrain. An engine converts fuel into motio
n. rather than Module x partly helps with s
mooth transport and motion generation.
Module y does too. Example one part of structu
re opens cans the other opens bottles.
Design Processes Map these desired fu
nctions onto a design which can then be manufa
ctured into an artefact which can then be sol
d as a product.
FR1 FR2 FRn
DP1 DP2 DPm
FR functional requirement (eg. FR1Should op
en cans) DP Design parameter (eg. DP1Shoul
d have sharp
point for puncturing can top.)
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CS228 Human-Computer Interaction
Software design
Converge on set of functional requirements
first The system should do X Design Princ
iples When programming, iterate through the cyc
le of Coding - Compiling - Executing - Debugg
ing as often and as quickly as possible Iterate
tightly and often Data hiding Hide the guts
of your code from the user interface
Hide the internals of a function away from its
interface. Design Process The waterfall mode
l 1. Create a set of written requirements (speci
fication) 2. Design the system architecture (des
ign) 3. Implement the system and test it (valida
tion) 4. Deploy the system to the public, and
update it based on feedback (deployment)
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CS228 Human-Computer Interaction
Interactive systems design
Design Principles Create the interactive syst
em such that a human can complete
the desired function while maximizing cer
tain global properties of the interactive
system eg. accessibility, usability, acceptabil
ity, engagement, etc. Design Process
Prototyping and Envisionment
Requirements
Evaluation
user testing
Physical Design
Conceptual Design
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CS228 Human-Computer Interaction
Interactive systems design
maximizing certain global properties of the
interactive system eg. accessibility, usability
, acceptability, engagement, etc.
How can people be unintentionally excluded from
using a technology? Physical exclusion ATM t
oo high for a child, or someone in a wheelchair.
Mouse may be too big for someones hand.
Joystick may be too difficult to operate for
someone with cerebral palsy. Conceptual exclusio
n Cause and effect relationships are confusing t
o some people. (eg. Different effects caused by
a slow or fast double-click) Cannot form a ment
al model of the system (eg. multiple menu paths
to do the same thing) Economic exclusion Cann
ot afford the technology (One Laptop Per Child
www.laptop.org) Cultural exclusion Making inap
propriate assumptions about interpretation
How will textual and visual analogies be
interpreted? Social exclusion Technology not a
vailable at the right time or place
Too many people need access to too few computers
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CS228 Human-Computer Interaction
Interactive systems design Example of visual anal
ogies User Interface for One Laptop Per Child
SUGAR
How would you interpret these icons?
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CS228 Human-Computer Interaction
Interactive systems design
maximizing certain global properties of the
interactive system eg. accessibility, usabilit
y, acceptability, engagement, etc.
A usable system will be one which is Easy to
use, easy to learn, flexible, and engenders a
good attitude in people. (Shackel, 1990) Bett
er to not rely on this vague definition rather,
optimize the usability factors
1. Efficiency people will get activities done w
ith a reasonable amount of effort.
2. Effectiveness Contains appropriate functions
and content, organized appropriately.
3. Easy to learn how to do things easy to remem
ber how to do things. 4. Safe to operate in the
variety of contexts in which it will be used.
5. High utility it does the things people actua
lly want to get done. (Processes supported by sy
stem lead the user toward their goals.)
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CS228 Human-Computer Interaction
Interactive systems design
maximizing certain global properties of the
interactive system eg. accessibility, usabilit
y, acceptability, engagement, etc.
How to achieve usability? (Gould et al., 1987
) 1. Early focus on users and tasks include user
s in design process who is doing what?
2. Empirical measurement. Record and analyze use
rs reactions to prototypes. Update the prototyp
es accordingly. 3. Iterative design Design,
test, measure, and redesign as rapidly and often
as possible. 4. All usability factors should b
e optimized together. Factors are interdependent
improving one factor may adversely affect anot
her factor. Q Using the factors from the prev
ious slide, where and how might this occur?
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CS228 Human-Computer Interaction
Interactive systems design
maximizing certain global properties of the
interactive system eg. accessibility, usabilit
y, acceptability, engagement, etc.
If all usability factors are optimized, the tech
nology becomes invisible i.e., the activity (and
its progress) is the focus, rather than the
supporting technology. Examples of highly usabl
e physical technologies A hammer Hammering in
a nail, rather than using a hammer.
A car Driving, rather than operating a
vehicle. When the technology is good, we tend t
o use verbs to describe the interaction,
rather than the interaction itself.
Only when things go wrong do we focus on the tec
hnology itself - When you mash your thumb, beco
me very conscious of hammers shape/weight
- When you skid out in a car, you become very
conscious of how you operate it.
Q What are some good software examples of where
this happens?
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CS228 Human-Computer Interaction
Interactive systems design
maximizing certain global properties of the
interactive system eg. accessibility, usability
, acceptability, engagement, etc.
Acceptability How acceptable is the technology
to the users? Differs from usability Cannot be
evaluated in a lab setting, like usability can
Must be evaluated within the context
where it will be used. Features of acceptabilit
y Political Do people trust the new technology?
Is it being forced on them? Convenience Is the
software awkward? Does it force a different path
toward the users goals? Does it disrupt their no
rmal sensory/motor processes for conducting the
task? (eg. Holding a book, reclining in a chair,
turning pages vs. sitting up straight, looking
at a screen, pressing buttons.)
Cultural and social habits Does the technology
mesh with the way people like to live?
Is the technology rude? Does it interrupt,
assume, ignore, the user? Economic Is the te
chnology affordable? Does it change the adopter
s business model for the better or worse?
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CS228 Human-Computer Interaction
Interactive systems design

• maximizing certain global properties of the
  interactive system
  
• eg. accessibility, usability, acceptability,
  engagement, etc.
  
• Does the system pull the user in? I.e., provide
  them with an engaging experience?
  
• Very subjective, and therefore the most difficult
  to quantify and measure.
  
• Does the user feel a sense of immersion,
• such as that produced by good movies/music/books?
  
  
• Does the user feel intellectually challenged, or
  creatively inspired by a good game?
  
• Does time seem to fly by when the software is
  used?
  
• Does the task feel like its flowing, or jerking
  forward bit by bit?
  
• Factors of engagement
• Identity Is your own personality reflected in
  the software?
  
• Adaptivity Does the system continue to
  challenge
  
• you at different levels of experience?
• Narrative Does the system tell a good story?
• Is there structure to the task progression?
• Immersion Does the software draw you in?