User Interfaces 4

1. User Interfaces 4 BTECH: IT WIKI PAGE: https://userinterfaces4.wikispace.com

2. UNIVERSAL ACCESS • Inclusive design • Interaction styles • Interaction devices • Interface feedback • Response times

3. Inclusive Design • Adapting existing designs: patchy, expensive • HCI interaction paradigms applied to assistive techniques • Guidelines: Can be very theoretical

4. Some steps for inclusive design • Adaptation needs to be “designed into‘” the system rather than decided upon and implemented afterwards • Requires an understanding of the global execution context of a task • Breaking away from the traditional perspective of “typical” users interacting • Non-platform specific • Broaden rage of graphical toolkit. (Stephanidis, C. 2000. Adaptive Techniques for UniversalAccess. User Modeling and User-Adapted Interaction , 11: 159-179)

5. Suggested Guidelines • User characteristics: the level of expertise the target audience have in the subject area of the Web site? • Domain requirements: What is the purpose of the Web site? What tasks are to be performed using the site? • Technology requirements: browsing and assistive technology • Pre-existing alternatives: What other ways already exist to provide access to the information or services of the Website? (multimedia clips, telephone information line) • Quality of alternatives: What other ways could be created to provide alternative routes to the same goals to which the site is intended to provide access? What are the accessibility (or other) barriers to accessing these alternative means? (Sloan, D., Heath, A., Hamilton F., Kelly, B., Petrie, H. and Phipps, L. 2004. Contextual Web Accessibility -Maximizing the Benefit of Accessibility Guidelines [online]. Available at http://www.w4a.info/2006/ [Accessed 1 Sept 2013])

6. Interaction Styles • Command Line – DOS, NETWORKS • Menus • Natural Language - different nuances • Question/Answer style - Query language to construct query • Form Fill-in - data capturing • WIMP - Windows, Icons, Menus and Pointing devices

7. Exercise For each of the previous interactions styles, list at least 2 advantages and disadvantages

8. Interaction Styles: Menus • Single: Binary multiple Item multiple selection pull down and popup scrolling and 2dimensional, alpha sliders embedded links • Multiple: Linear sequence tree acyclic cyclic

9. Menu Layout • Titles • for single menus - descriptive title • linear sequence - titles should accurately represent the stages in the sequence • tree-structured menus: • the root must be clearly stated, e.g. MAIN etc. • use same words in high-level menu items as in titles for next lower level menus • be consistent with placement of titles

10. Menu Layout (Cont.) • Phrasing of menu items • Use familiar and consistent terminology • Ensure that items are distinct from one another • Use consistent and concise phrasing • Bring the keyword to the left

11. Menu Layout (Cont.) • Guide lines for consistency: • Titles: centred or left justified • Item placement: left, may use blank lines in between, numbers • Instructions: identical, same position • Error messages: consistent position, terminology and syntax • Status reports: consistent position and structure • Progression • Successive menus can be cascades, walking or transparent menus. Walking menus can present a motor challenge. Transparent menus should not be higher than 50%.

12. Interaction Devices • Keyboards – qwerty, audio feedback • Pointing Devices: direct: light pen, touch screen indirect: mouse, trackball, joystick, touchpad • Touch screen: Smudges, hand obscures, accuracy • Speech recognition and generation • Gaming devices

13. Interaction: Speech • Discrete-word recognition Individual words spoken by specific person When/where: handicapped people, speaker’s hand are busy, mobility is required, speaker’s eyes are occupied, harsh or cramped conditions preclude keyboard Background noise influences accuracy • Continuous-speech recognition Dictating letter, limited

14. Speech (Cont.) • Speech store and forward messages stored and forwarded like weather, airlines, voice mail, audio tours in museums • Speech generation When: message is simple, short, will not be referred to later, deals with events in time, requires an immediate response, visual

15. Interface Feedback • Error Messages • Colour • Design • Data display

16. Feedback: Error Messages Phrasing of error messages or diagnostic warnings is critical: • Why do users make errors?: lack of knowledge, incorrect understanding, inadvertent slips • Errors lead to feelings of inadequacy, confusion and anxiety • Too imperious tone condemning the user increases anxiety resulting in further errors • Too generic messages don’t give enough information to correct the error • Obscure messages like FACRJCT 0004444 offer no assistance.

17. Guidelines for error messages • Be specific about what caused the error: e.g. • Use constructive guidance and positive tone, the user needs guidance to correct the error • User-Centered phrasing: don’t use ENTER DATA, rather use READY TO ACCEPT DATA • Appropriate physical format: Reserve capital letters for serious warnings, avoid using error codes, placement of error messages • Develop effective error messages by involving the users

18. Guidelines for error messages(Cont.) • Multiple levels of messages • Consistent grammatical form, terminology and abbreviations • Consistent visual format and placement Exercise: Find at least 3 error messages in any applications and evaluate them against these guidelines.

19. Feedback: Colour • Place colour coding under user control • Consider the needs of colour-deficient users • Limit the number of colours no more than 4 • Use colour as a coding technique, e.g. all addresses a particular colour, or all labels one colour and all data-entry fields another • Ensure that colour coding supports the task, e.g. the active window a different colour from the inactive one, when status of an item changes, change its colour • Common expectations about colour codes, e.g. warning messages in red – cultural!!!

20. Feedback: Design Non-anthropomorphic Design • avoid presenting computers as people • choose appropriate humans for introductions and guidelines (culturally and gender sensitive) • use caution in designing computer-generated human faces or cartoon characters • design comprehensible, predictable and controllable interfaces • provide user-centred overviews for orientation and closure • do not use “I” when the computer responds to human actions • use “you” to guide users or just state facts

21. Feedback: Data Display • Keep complexity low • directly usable form • order lists • label each page in multi-paged display • maintain consistent format

22. Response Times • Response Time = the number of seconds it takes from the moment the user initiates an activity until the computer begins to present results. • User Think Time = the number of seconds during which users think before entering the next action. • Users plan while reading results, while typing, and while the computer is generating results or retrieving information across a network. • Precise measurement of User Think Time is difficult. Measurement of computer response time is easier, but distracting messages, informative feedback, etc. also influence results.

23. Response Times (cont.) • Factors influencing choice of optimum speed: • experience: novices may need slower response times, experienced users require rapid action • penalty for errors: if low penalty for errors then users prefer to work faster • task: typing, frequent, data capturing, problem solving tasks require different response times • Expectations and attitude • How long will users wait before becoming agitated? Varies • past experiences, varied response times for same task promotes agitation • delay tolerance: personality, age, cost, mood, culture, pressure, etc. • task complexity difference

24. Response Times (cont.) • Variability • users can adapt to variable situation: some take advantage of it • modest variations in response time (plus or minus 50%) appear to be tolerable with little effect on performance • with extreme changes users are able to adapt and complete their tasks, but frustration emerges.

25. Response Time Guidelines • Users prefer shorter response times • Longer response times (> 15 sec) are disruptive • Users change usage profile with response time • Shorter response time leads to shorter think time • A faster pace may increase productivity, but may increase error rates • Error recovery ease and time influence optimal response time • Response time should be appropriate for the task: • Typing, cursor motion, mouse selection: 50-150 milliseconds • simple frequent tasks: 1 second • common tasks: 2-4 seconds • complex tasks: 8-12 seconds • Users should be advised of long delays • Modest variability in response time is acceptable • Unexpected delays may be disruptive • Empirical tests can help to set suitable response times