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Introduction. CSCI 488/688: Human-Computer Interaction Instructor: Jun Kong. Outline. Introduction Usability Requirements Usability Measures and applications Universal Usability. Human-computer interaction. Human-computer interaction. Human-Computer Interaction. Pen-based Interaction.
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Introduction CSCI 488/688: Human-Computer Interaction Instructor: Jun Kong
Outline • Introduction • Usability Requirements • Usability Measures and applications • Universal Usability
Human computer interaction (HCI) • Human computer interaction (also known as user interface design) is the study of interaction between users and computers. • Interactive computer systems • Users initiate some action and system responds with some output • System prompts users to do something, and users have to respond with more inputs • These interactions take place through the user interface. • An Interdisciplinary Design Science: Psychologists, Computer Scientists, Instructional and Graphic Designers, Technical Writers, Human Factors and Ergonomics Experts, Anthropologists and Sociologists
User interface design efforts • UI accounts for 50% of: • Design time • Implementation time • Maintenance time • Code size • A killer robot -Myers & Rosson, “Survey on user interface programming”, CHI ’92.
Successful applications • Windows XP • Google • Amazon • Warcraft • etc……
Failure in user interface • What am I supposed to do now? • Where is the information of interest? • Vague messages
Design for Multiple Devices? Source: www.cs.berkeley.edu/~landay/research/talks/intel-seattle-patterns/patterns-damask-intel2003.ppt
Multi-model • Humans perceive the world through senses. • Touch, Smell, Sight, Hearing, and Taste • Communication through one sense in known as a mode. • Computer may process information through modes as well • Keyboard, Microphone, Camera etc. • Multimodal Interfaces try to combine two different modes of communicating.
Outline • Introduction • Usability Requirements • Usability Measures • Usability Motivations • Universal Usability
Goals for requirement analysis • Ascertain the users’ needs • Ensure proper reliability • Promote appropriate standardization, integration, consistency and portability • Complete projects on schedule and within budget
Ascertain the user’s needs • Determine what tasks and subtasks must be carried out • Include tasks which are only performed occasionally. Common tasks are easy to identify. • Functionality must match need or else users will reject or underutilize the product Providing excessive functionality is a danger
Ensure reliability • Actions must function as specified • Database data displayed must reflect the actual database • Appease the user's sense of mistrust • The system should be available as often as possible • The system must not introduce errors • Ensure the user's privacy and data security by protecting against unwarranted access, destruction of data, and malicious tampering
Promote standardization, integration, consistency, and portability • Standardization: • Common user-interface features across multiple applications • Use pre-existing industry standards where they exist to aid learning and avoid errors • Integration: the product should be able to run across different software tools and packages
Promote standardization, integration, consistency, and portability • Consistency: • Compatibility across different product versions • Compatibility with related paper and other non-computer based systems • Use common action sequences, terms, units, colors, etc. within the program • Portability: allow for the user to convert data across multiple software and hardware environments
Complete projects on time and within budget Late or over budget products can create serious pressure within a company and potentially mean dissatisfied customers and loss of business to competitors
Outline • Introduction • Usability Requirements • Usability Measures • Usability Motivations • Universal Usability
User-friendliness • “user-friendly”: easy to use; easy to learn; comprehensible; intelligible; and etc • The notion of “user friendliness” is vague and subjective. • Explicit and clear goals are necessary to develop usable systems for specific users in a specific context
Usability measures • Define the target user community and class of tasks associated with the interface • 5 human factors central to usability evaluation: • Time to learnHow long does it take for typical members of the community to learn relevant task? • Speed of performanceHow long does it take to perform relevant benchmarks? • Rate of errors by usersHow many and what kinds of errors are made during benchmark tasks? • Retention over timeFrequency of use and ease of learning help make for better user retention • Subjective satisfactionAllow for user feedback via interviews, free-form comments and satisfaction scales
Trade off • Trade-offs in design options frequently occur. • Learning time V.S. speed of performance • Speed of performance V.S. rate of errors • New functionality V.S. consistency • Design alternatives can be evaluated by designers and users via mockups or high-fidelity prototypes.
Applications • Different applications may have different usability goals • Life-critical systems • Industrial and commercial uses • Office, home, and entertainment applications • Exploratory, creative, and cooperative systems • Social-technical systems
Life-critical systems • Air traffic control, nuclear reactors, power utilities, police & fire dispatch systems • High costs, reliability and effectiveness are expected • Usability goals: • Rapid Error-free performance • Lengthy training periods are acceptable • Subject satisfaction is less an issue due to well motivated users • Retention is obtained by frequent use
Industrial and commercial uses • Banking, insurance, order entry, inventory management, reservation, billing, and point-of-sales systems • Usability goals: • Ease of learning is important to reduce training costs • Speed of performance is important because of the number of transactions • Subjective satisfaction is fairly important to limit operator burnout
Office, home, and entertainment applications • Word processing, electronic mail, computer conferencing, and video game systems, educational packages, search engines, mobile device, etc. • Usability goals: • Ease of learning, low error rates, and subjective satisfaction are paramount because use is often discretionary and competition is fierce • Choosing the right functionality
Exploratory, creative, and cooperative systems • Web browsing, search engines, artist toolkits, architectural design, software development, music composition, and scientific modeling systems • Usability goals: • Hard to evaluate those systems due to the exploratory nature of those applications • With these applications, the interface should "vanish" so that the user can be absorbed in their task domain
Social-technical systems • Complex systems that involve many people over long time periods, such as systems for Voting, health support, identity verification, crime reporting • Usability goals: • Ease of learning for novices and feedback to build trust • Administrators need tools to detect unusual patterns of usage
Outline • Introduction • Usability Requirements • Usability Measures • Usability Motivations • Universal Usability
Universal usability • Diverse users: physical abilities, backgrounds, motivations, personalities culture, work style and etc • Considering interfaces for different situations often results in a better product • Curb cut in sidewalks for wheel-chair users • Baby strollers, skateboard riders, travelers with wheeled luggage • Ultimate goal – addressing the needs of all users
Physical abilities • Hundreds of features: male and female, young and adult …… • Either compromises must be made or multiple versions of a system must be created • Keyboard • Chair
Gender Differences • Example: Games for girls • Purple Moon • SIMS • 56 percent of the Sims audience are teenage girls • Games for boys
Games - SOME INDUSTRY FACTS • Seventy-five percent of American heads of households play computer and video games. • In 2004, more than 248 million computer and video games were sold, almost two games for every household in America. • The average game player is 30 years old and has been playing games for 9.5 years. • The average game buyer is 37 years old. In 2005, 95 percent of computer game buyers and 84 percent of console game buyers were over the age of 18. • Forty-three percent of all game players are women. In fact, women over the age of 18 represent a greater portion of the game-playing population (28 percent) than boys from ages 6 to 17 (21 percent). • In 2004, 19 percent of Americans over the age of 50 played video games, an increase from nine percent in 1999 • Females spend an average of two hours more per week playing games now than they did a year ago.
Cognitive and perceptual abilities • The human ability to interpret sensory input rapidly and to initiate complex actions makes modern computer systems possible • In any application, background experience and knowledge in the task domain and the interface domain play key roles in learning and performance
Personality differences • Personality: Feeling VS. Thinking; Perceptive VS. judging; sensing VS. intuition • Different personalities can lead to different behavior: • File emails in a well-organized hierarchy • Keep them all in the box and use search strategies to find what they want later
Cultural and international diversity • Characters, numerals, special characters, and diacriticals • Left-to-right versus right-to-left versus vertical input and reading • Date and time formats • Numeric and currency formats • Weights and measures • Telephone numbers and addresses • Names and titles (Mr., Ms., Mme.) • Social-security, national identification, and passport numbers • Capitalization and punctuation • Sorting sequences • Icons, buttons, colors • Grammar, spelling • Etiquette, policies, tone, formality, metaphors
Internationalization of Icons Source: http://www.stanford.edu/class/cs147/
Universal Usability (cont.) • Users with disabilities • Designers must plan early to accommodate users with disabilities • Early planning is more cost efficient than adding on later • Businesses must comply with the "Americans With Disabilities" Act for some applications • Elderly Users • Designer should allow for variability within their applications via settings for sound, color, brightness, font sizes, etc.
Key points • Usability requirements: Ascertain the users’ needs; Ensure proper reliability; Promote appropriate standardization; integration, consistency and portability; and Complete projects on schedule and within budget • Usability measures: Time to learn; Speed of performance; Rate of errors by users; Retention over time; and Subjective satisfaction • Different applications have different usability goals • Diversity is a challenging issue in the interface design
Tabbed dialog Source: Interface Hall of Shame
A better design Source: Interface Hall of Shame
Vague error messages Source: Interface Hall of Shame
Inconsistency Source: Interface Hall of Shame
Redesign Source: Interface Hall of Shame
Gimp - an open-source image editing program Source: http://courses.csail.mit.edu/6.831/