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CS313 Introduction to Human Computer Interaction. Introduction. What is this class about?. Brief overview of Human Computer Interaction techniques Understanding of what usability is and means Awareness of Good and Bad design
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CS313Introduction toHuman Computer Interaction Introduction
What is this class about? • Brief overview of Human Computer Interaction techniques • Understanding of what usability is and means • Awareness of Good and Bad design • You will be able to create better user interfaces, web sites, consumer products, etc.
Who are “Users”? • People who will use a product or web site. • As opposed to the “Designers” • People who create the system or web site • Have to make an effort to Know The User
The Human • Information i/o via • visual • auditory • haptic • movement channels • Information stored in memory • Information processed and applied
“Which direction?” “Help” “Boat"
Memory There are three types of memory function: Sensory memories (buffers for stimuli: visual iconic,auditory echoic, touch haptic) Short-term memory or working memory Long-term memory Selection of stimuli governed by level of arousal. Attention Rehearsal
Short-term memory (STM) Scratch-pad for temporary recall rapid access ~ 70ms rapid decay ~ 200ms limited capacity - 7± 2 chunks
Long-term memory (LTM) Repository for all our knowledge slow access ~ 1/10 second slow decay, if any huge or unlimited capacity Two types episodic - serial memory of events semantic - structured memory of facts,concepts, skills information in semantic LTM derived fromepisodic LTM.
What is the “User Interface”? • Everything the user encounters • Functionality • Content • Labels • Presentation • Layout • Navigation • Speed of response • Documentation & Help
The Computer • a computer system is made up of various elements • each of these elements affects the interaction • input devices - text entry and pointing • output devices - screen, audio • paper input and output • memory - RAM, permanent storage media • processing - speed of processing, networks
Dvorak • common letters under dominant fingers • biased towards right hand • common combinations of letters alternate between hands • 10-15% improvement in speed and reduction in fatigue
What is “Usability”? • = Quality! • Learnability • Efficiency • Productivity • Memorability • Little “re-learning” required • Satisfaction • Pleasurable
Skinput: Appropriating the Body as an Input Surface • CHI’2010 • Chris Harrison, HCII, Carnegie Mellon University, USA • Desney Tan (formerly CMU), Dan Morris, Microsoft Research, USA • Use a tiny projector on body to show menus • Microphones to listen to taps on hand/arm • Signal processing and machine learning todifferentiate positions
Why are Interfaces Important? • Sit-down-and-use computers and software • Don't read the manuals • Usability is critical to software sales: • In magazine ratings • "User friendly" • HCI-trained people build better interfaces • Programmers don't think like end-users • Exposure to different kinds of interfaces, problems • User model, not system model
Problem • Appliances are too complex
Problem • Too many remotes
Good UIs on Successful Products • Palm succeeded where other handhelds had failed due to a focus on usability: • Fit into pocket • Reliable gestural text input • Commands immediately available • Apple iPod lauded fordesign and user interface • Apple iPhone – • Wii controller, vs. XBox, PS3graphics & power
Why Hard to Design UIs? “It is easy to make things hard. It is hard to make things easy.” • User Interface design is a creative process • Designers have difficulty thinking like users • Often need to understand task domain • Can’t “unlearn” something
Why Difficult • Tasks and domains are complex • Word 1 (100 commands) vs. Word 2007 (>2000) • MacDraw 1 vs. Illustrator • BMW iDrive adjusts over 700 functions • Existing theories and guidelines are not sufficient • Too specific and/or too general • Standard does not address all issues. • Adding graphics can make worse • Pretty Easy to use • Can’t just copy other designs • Legal issues