Transcript No Slide Title

Chp.2: Components of HCI
Spring 2002
• How to achieve HCI goal of developing or improving systems
(safety, utility, effectiveness, efficiency, usability, etc.) AND
make sure system integrates well into organizational settings in
which it’s used?
• A multi-disciplinary perspective is used -- analyze problems
from different perspectives, including consideration of range of
factors:
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organization (training, job design, politics)
environment (noise, lighting, ventilation)
health & safety (stress, headaches, fatigue)
human & comfort factors (motivation, enjoyment, satisfaction, proficiency)
user interface (input, output, color, graphics, etc.)
task factors (easy, complex, etc.)
constraints (cost, timescales, budgets, staff, equipment)
system functionality (hardware, software, application)
productivity factors (ouput levels, cost, production time)
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Chp.2: Components of HCI
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Spring 2002
Four examples (3 from old text, 1 from new text):
– airline ticket reservations
– supermarket checkout
– paper interface (should be PDA)
– cell phones
Each case considered in terms of a range of HCI factors:
– human (e.g., staff, customer)
– user interface
– work activity
– organization
– comfort
– productivity
– etc…
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Chp.2: Components of HCI
Spring 2002
• Airline reservation system
• Before:
– customer went to travel agency
– gave desired destination and travel times to agent
– agent called airline
– check with customer to see if times ok
– if seats/time not ok, repeat…
– ticket accounting: agents fills out paper forms,
sends to airlines bi-weekly
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Chp.2: Components of HCI
Spring 2002
• Airline reservation system
• Now:
– customer goes on-line
– use types in desired times, destination
– wait for search engine
– like times, prices? if not repeat.
– press buttons to give payment info
– ticket accounting: issued electronically, airline dB
updated immediately
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Chp.2: Components of HCI
Spring 2002
• Airline reservation system
• HCI factors:
– human (staff): possibly out of work
– human (customer): enjoys immediacy of seat selection, but
has to do more work him/her-self
– UI: keyboard, web forms, etc.
– work activity: more work placed on user
– organization: training needs - user has to know, learn how to
use system; impersonal (some people prefer F2F interaction
with travel agent)
– comfort: use has to have computer, may interfere with
current task
– productivity: user has to take time away from other tasks
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Chp.2: Components of HCI
Spring 2002
• Supermarket checkout
• Goal: automate pricing/inventory procedures
• Infrastructure requirements:
– all items in store must be barcoded
– dB must exist to handle purchases/pricing
– need scanning systems installed
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Chp.2: Components of HCI
Spring 2002
• Supermarket checkout
• Discussion:
– What are effects on:
• user (staff)?
• user (customer)?
• is the user interface easy to learn/use?
• how are problems handled (e.g., mis-scanned product,
incorrect price)?
• what is the work activity - is training required? for
whom? (customer, staff, both?)
• comfort: how is cashier affected?
• system: what is needed (expensive? difficulty of install?)
• productivity and “spin-off” factors: is process more
streamlined? What about marketing analysis (BiLo
card)?
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Chp.2: Components of HCI
Spring 2002
• Xerox Parc’s paper user interface (PalmPilot more
appropriate)
• Discussion:
– What are effects on:
• technology: what is required for development of
PDA such as the PalmPilot (hardware,
software)?
• what is the user-interface: easy to learn?
• organization: is user’s “world” better
organized?
• comfort: easy to handle, transport?
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Chp.2: Components of HCI
Spring 2002
• Cell phones (they’re great to pick on right now :)
• Discussion:
– major usability drawbacks:
• restricted access (getting better)
• very small LCD screen
• mostly text-based (image/video based starting to appear,
however, is this more expensive, i.e., pay for time to
download?)
– assumptions used:
• people want to use device while mobile
• people want to interact with info while on the move
• users will trade screen real estate for information (???)
• phones will offer comparable interaction to PCs (???)
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Chp.2: Components of HCI
Spring 2002
• In evaluating multiple factors, various disciplines
contribute to HCI:
– Computer Science (dB, O/S, AI, Grahpics, …)
– Psychology (Cognitive, social, organizational)
– IE (Ergonomics, human factors)
– Design
– Anthropology
– Sociology
– Philosophy
– Linguistics
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Chp.2: Components of HCI
Computer Science
Spring 2002
• Mostly system/technology level
– programming languages, compiler, etc.
– O/S
– Networking
– WWW
– GUI toolkits and window managers
– multimedia
– graphics
– VR (new devices, incl. sensors, effectors, haptics)
• Application: use whatever devices/techniques suit
the application
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Chp.2: Components of HCI
Cognitive Psychology
Spring 2002
• Understanding human behaviour, underlying mental
processes, and capabilities and limitations thereof:
– perception
– attention
– memory
– learning
– thinking
– problem solving
• Application: apply principles to design, e.g., memory
and attention are limited, don’t “clutter” UI with > 7
+/- 2 things at a time
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Chp.2: Components of HCI
Social and Ogranizational Psychology
Spring 2002
• Understanding human behaviour in social contexts:
– individual’s influence on another
– individual’s influence on group (e.g., leadership
qualities, or “weakest link”)
– group’s influence on individual (e.g., peer
pressure)
– relationship between different groups (e.g.,
different preferences, tastes, as in high school
jocks, geeks, etc.)
• Application: consider how computers affect
oranizations, groups of people…
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Chp.2: Components of HCI
Ergonomics & Human Factors
Spring 2002
• Maximize operator’s safety, efficiency, reliability,
performance, satisfaction, etc., e.g., ergonomic
cockpits, office furniture, etc.
• Application: evaluate devices/interaction from
ergonomic perspective, e.g.,:
– “VDUs” (monitors) that minimize eye strain
– devices that don’t cause carpel tunnel
– VR simulators that promote training, test human
performance
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Chp.2: Components of HCI
Linguistics
Spring 2002
• Study of language, understanding structure (syntax)
and meaning (semantics)
• Application: apply to human-interface dialogue (how
does system “speak” to user):
– natural language interface (voice recognition, e.g.,
e.Digital’s MXP 100 MP3 player)
– query languages (dB)
– internationalization (locales)
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Chp.2: Components of HCI
Philosophy, Sociology, Anthropology
Spring 2002
• “Soft science”?
• Usually considers social implications of IT, e.g.,
– are workers being displaced?
– are we becoming less social (more time in email than F2F)?
– Increasingly important especially in domains such as
CSCW, I.e., how do people interact, communicate,
collaborate
• Application: apply to computer-supported human-human
interface dialogue (how do humans communicate):
– eye-to-eye contact?
– deictic (“look at that”) references?
– e.g., Hiroshi Ishii’s TeamWorkstation: maintained eye
contact in video telephony applications
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Chp.2: Components of HCI
Conceptual Model of HCI
Spring 2002
• HCI is neither the study of humans, nor of
technology, rather it is the bridging between the two
(to paraphrase Terry Winograd)
• Design concept: know how to make transition from
what can be done technologically to how to make it
usable for users in their environment
• Lowest level: select most appropriate input (VR, pen,
mouse) and output device (video, speech, text), then
decide on interaction style (natural language, GUI,
VR, multimedia), knowing human psychology and
particular human characteristics relevant to task at
hand (e.g., for text display, don’t use green on red)
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Chp.2: Components of HCI
Conceptual Model of HCI
Spring 2002
• To develop a conceptual model involves envisioning
the proposed product, based on users’ needs and
other identified requirements
– one particularly useful HCI technique is to
develop prototypes
• Key aspect: task-based analysis---what will users be
doing when carrying out their tasks?
• Once interaction requirements have been defined:
– consider “look and feel” of interface
– consider interface metaphor (e.g., desktop)
– consider conceptual metaphor
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Chp.2: Components of HCI
Conceptual Models
Spring 2002
• Conceptual models based on activities:
– instructing (e.g., a system to do something; cmds)
– conversing (e.g., with system; help page, menu)
– manipulating and navigating (e.g., direct manip)
– exploring and browsing
(not mutually exclusive)
• Problems:
– instruction set: prone to (syntax) errors?
– conversations: prone to semantic errors?
– direct manipulation (click+drag): too literal?
– exploring and browsing: how to allow navigation?
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Chp.2: Components of HCI
Conceptual Models
Spring 2002
• Conceptual models based on objects:
– spreadsheet (killer app based physical ledger)
– Quicken (paper checks and registers
• Conceptual models may require a mix of models of
objects and actions
– but use caution: this may lead to numerous ways
of doing things, e.g.,
• speak “delete file” (conversation?)
• press CTRL-D (command)
• drag file to trash (direct manipulation)
– this may result in steeper learning curve
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Chp.2: Components of HCI
Conceptual Models
Spring 2002
• Interface metaphors:
– another way of conceptualizing interface
– can be based on actions, objects, or both
– usually based on combination of familiar
knowledge with new concepts (using analogies to
bridge gap between)
• Examples:
– desktop metaphor (this one’s a popular example):
• dragging a file to trash (same as real action)
• highlighting text
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Chp.2: Components of HCI
Conceptual Models
Spring 2002
• Interaction paradigms:
– a more general abstraction of conceptual model
– a particular philosophy (prone to shifting :)
– examples:
• applications for the desktop; GUI, WIMP
• now moving “beyond the desktop”, e.g.,
– Body-Area Network (BAN)
– ubiquitous computing (embedded tech.)
– pervasive computing
– wearable computing
– AR / VR
– tangible user interfaces
– haptic interfaces
– attentive environments (attentive displays)
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Chp.2: Components of HCI
Design process
Spring 2002
• 4 components:
– people
– work (the task)
– environment (physical, organizational, social)
– technology
• The HCI design process: not quite as linear as software
engineering’s “waterfall model”
• Key differences:
– user-centered design: involve users as much as possible
– integration of multidisciplinary knowledge
– iterative design: periodically check with user
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Chp.2: Components of HCI
Design process
Spring 2002
• Inolving users:
– decide who end user is, how product will be used, made,
sold, marketed
– observe current user practices - leads to system
requirements (how can current practice be improved?)
– can use psychological models of human, e.g., follow & test
such concepts as Fitt’s Law
– include user representatives on team:
• end users
• management
• marketing personnel
• graphic designers, etc.
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Chp.2: Components of HCI
Design process
Spring 2002
• Incorporating interdisciplinary knowledge:
– computer science (AI, graphics, O/S, dB, etc.)
– psychology
– human factors
– linguistics
– philosophy
– sociology
– anthropology
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Chp.2: Components of HCI
Design process
Spring 2002
• Iterate the design process:
– use the Star model: featuring iterative evaluation
(as center of star)
– components:
• requirements specification
• task analysis / functional analysis
• conceptual design / formal design
• implementation
• prototyping
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