3.Profil Pengguna

8/2/2019 3.Profil Pengguna

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IS 3323

Interaksi Manusia Komputer

3rd Session

FAU


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Human Capabilities

-Senses

-Memory-Motor Systems


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Human Capabilities

Why do we care? better design!

Want to improve user performance

Knowing the user informs the design

SensesInformation processing

Physical responding

Time and effort expendedto complete tasks


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I. Senses

Sight, hearing, touch important forcurrent HCI

smell, taste ???

Abilities and limitations

affect design


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Vision

Visual System

Eye

Retina

Neural pathway

~ 80% of brains operation


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Visual Abilities

SensitivityLuminance: 10-6~107 mL

Absolute threshold: 10-6 mL

Comfortable reading: 1~100 mL

Colorless vision 10-6

~ 10-1

mLColor vision 1 ~ 107 mL

Acuitydetection, alignment, recognition (visual angle)

Ability to sense the details

Foveal

visionretinal position: foveahas best acuity

Peripheral visionSenses the area surrounding the location we looking at


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Movementtracking, reading, vibrations

Note: Vision decreases with age

Implications (??)

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Visual Abilities


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Visual Ability

Cobalah untuk membaca tulisan berikut ini lalubandingkan dengan teks yang akan munculberikutnya.

Adakah yang bisa membaca teks yang muncul berikut ini, berikan pendapatmu mengenai hal inidan kaitannya dengan mata kuliah imk.

Kalau modelnya begini bagaimana ? Apakah masih

seperti yang sebelumnya. Manakah yang lebih gampang dibaca ?

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Ponzo Illusion

Manakah yang lebih panjang ?

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Hearing

Capabilities (best-case scenario)pitch - frequency (20 - 20,000 Hz)

loudness - amplitude (30 - 100dB)

location (5 source & stream separation)

timbre - type of sound (lots of instruments)

Often take for granted how good it is(disk whirring)

Implications (??)


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Touch

Three main sensations handledby different types of receptors:

Pressure (normal)

Intense pressure (heat/pain)

Temperature (hot/cold)

Sensitivity, Dexterity,Flexibility, Speed

Where important?Mouse, Other I/O, VR, surgery


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II. Memory


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Information Processing

Three major systems of humaninformation processing:

Perceptual (read-scan)Cognitive (think)

Motor system (respond)


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1. Perceptual

is our awareness and understanding of the elements andenvironment through the physical sensation of our various sense

Memory structures

Sensory buffer - Holds fixed image of outside world long enough forsome analysis

Our sensing mechanism are bombarded by many stimuli

Signal: important stimuli

Noise: not important or unwanted stimuli

Processes - Info goes to brain for more processinge.g. Pattern recognition

Uses context & knowledge

Could be different with others try these:


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2. Cognitive

Cognitive model

How does it work?


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Memory

Four typesPerceptual buffers (sensory storage)

Brief impressionsShort-term memoryConscious thought, calculations

Intermediate

Storing intermediate results, future plansLong-termPermanent, remember everything everhappened to us

Chess


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Short-term memory

Use chunks: 4-5 units (Koyani et al.2004)

Previous research by Miller (1956), human canhandle 72 units of chunks gradually lowered

Display format should match memorysystem used to perform task

New info can interfere with old info

Piece of information


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Format depends on peoplescharacteristics

V-K-A-DVisual: sensing as an image

Kinematic: sensing through touch

Auditory: sensing through audio/voiceDigital auditory: imaginary conversation

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Short-term memory


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Long-term Memory

Seemingly permanent & unlimited

Access is harder, slower

-> Activity helps (we have a cache)

File system full


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LT Memory Structure

Episodic memoryEvents & experiences in serial formHelps us recall what occurred

Semantic memoryStructured record of facts, concepts & skillsOne theory says its like a network

Another uses frames & scripts (like record structs)


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Memory Characteristics

Things move from STM to LTM byrehearsal & practice and by use in context

We forget things due to decay and

interference

Unclear if we everreally forget something Lack of use

Similar gets inway of old

Exercise


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Exercise

Put a number 1000 into your memory

Well do a simple math operation: add

Speak out loud every result youve count

Get ready

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Do it quick!!!

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1000

1000

40

301000

1000

20

10

+

++++

++

???


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Processes

Four main processes of cognitive system:

Selective Attention

LearningProblem Solving

Language


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Selective Attention

We can focus on one particular thing

Cocktail party chit-chat

Salient visual cues can facilitate s.a.

Examples?Boldface, blinking and beeping


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Learning

Two types:Procedural How to do something

Declarative Facts about something

InvolvesUnderstanding concepts & rules

Memorization

Acquiring motor skills

Automotization

Tennis


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Learning

Facilitated

By analogy

By structure & organizationIf presented in incremental units

Repetition

Use users previous knowledge ininterface


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Observations

Users focus on getting job done, notlearning to effectively use system

Users apply analogy even when it doesntapply


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Problem Solving

Storage in LTM, then application

Reasoning

Deductive-

Inductive-

Abductive-

If A, then BGeneralizing from previouscases to learn about new ones

Reasons from a fact to theaction or state that caused it


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Observations

People are more heuristic than algorithmic

Try a few quick shots rather than plan

Resources simply not available People often choose suboptimal strategies

for low priority problems

People learn better strategies withpractice

Implications??


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Implications

Allow flexible shortcuts

Forcing plans will bore user

Have active rather than passive help

Recognize waste


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III. Motor System

CapabilitiesRange of movement, reach, speed,strength, dexterity, accuracy

Often cause of errorsWrong button

Double-click vs. single click

PrinciplesFeedback is important

Minimize eye movement


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People

GoodInfinite capacity LTM

LTM duration &

complexityHigh-learningcapability

Powerful attention

mechanismPowerful patternrecognition

Bad

Limited capacity STM

Limited duration STM

Unreliable access toLTM

Error-prone processing

Slow processing


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Any Question ?

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3.Profil Pengguna

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