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SEG 3210

SEG 3210. User Interface Design & Implementation Prof. Dr. Abdulmotaleb El Saddik University of Ottawa (CBY A211) (613) 562-5800 x 6277 elsaddik @ site.uottawa.ca abed @ mcrlab.uottawa.ca. Unit E : Design Guidelines. A General Meta-Guideline Interaction Styles vs. Interaction Elements

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SEG 3210

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  1. SEG 3210 User Interface Design & Implementation Prof. Dr. Abdulmotaleb El Saddik University of Ottawa (CBY A211) (613) 562-5800 x 6277 elsaddik @ site.uottawa.ca abed @ mcrlab.uottawa.ca

  2. Unit E: Design Guidelines • A General Meta-Guideline • Interaction Styles vs. Interaction Elements • Coding Techniques and Visual Design • Response Time • Feedback and Error Handling • Command-Based Interfaces • Menu Driven Systems • Keyboard Shortcuts • Forms-Based Interfaces • Organizing a Windowing Interface • Question and Answer Interfaces • Information Query Interfaces • Voice I/O • Natural Language Interfaces • Other Types of I/O • Localization and Internationalization • On-Line Help • Guidelines and Standards Documents

  3. I/O Techniques, Devices, and Technologies • An interaction technique is • A way to carry out an interactive task • Based on using a set of: • input and output devices or • technologies. • Indirect Pointing devices • mice • trackballs • joysticks • … • Input devices • indirect pointing devices • direct pointing devices • keyboards • microphones • video cameras • body sensors • dolls (e.g., Barney) • … • Direct Pointing devices • tablets • touchscreens • touchpads • …

  4. Input technologies • speech recognition • speaker recognition • machine vision • eye tracking • head tracking • gesture tracking • touch sensing • pressure sensing • … • Devices that detect touch position: touchscreens, touchpads, tablets. • can have a display or just an input tablet • many devices also detect the amount of pressure used when touching • possibilities for pressure-sensitive interaction techniques • Touch-sensing: sensing touch in mice and trackballs (Ken Hinckley, Microsoft) • The programs can react on touching the device

  5. Output technologies • speech synthesis • audio-visual speech synthesis (e.g., a talking head, an artificial person) • haptic/tactile feedback • stereoscopic displays • … • Output processing hardware • sound cards • graphics cards • interface cards • ... • Output devices • monitors • earphones • loudspeakers • tactile devices: technology has advanced to the level that allows us to mimic real touch sensations when using computers • dolls (e.g, Barney) • …

  6. 13. Voice I/O • Consider voice input in the following circumstances: • Hands are busy • Environment is dirty • Small device with keyboard not available • Dictation by a slow typist • Structure voice command input so: • Only one or two words are required

  7. Voice I/O (Why Speech?) • Natural: • speech is the most efficient, popular and wide-spread way to communicate • Efficient: • in many cases speech is the most efficient communication method [Chapanis, 1975] • Expressive: • Some things are quite impossible to express without using speech (or natural language in general) • Popular and preferred: • Some people use verbal-acoustic problem solving methods instead of visual-spatial (GUI-oriented) methods [Bradford, 1995]

  8. Motives to use speech in user interfaces • The only possible method • The most efficient method • The most preferred method • A supportive method • An alternative method • A substitutive method It is important to know the motives behind the use of speech!

  9. Restrictions of speech in user interfaces • Restrictions related to the characteristics of speech • temporary, slow and serial • Public • the need to remember commands or key-words • Restrictions related to the communication skills • discrete vs. continuous style of speaking • interruptions • the use of pauses • Problems of speech recognition • Variations in speech-signal • Linguistic variations • phonetic, syntactic, semantic and discourse related variations • Acoustic variations • communication channel and environment related variations • Speaker related variations • internal and interpersonal variations Natural speech contains hesitations, false starts, repairs, breaks etc. ungrammatical elements

  10. Voice output • Consider voice output in the following circumstances: • Avoid voice output where the following are important: • Eyes are busy or user will be away from screen • Vision might not be possible • Blind, variable lighting, fumes • User has to perform a monitoring function • Sporadic warning signals are better picked up if they are vocal • Voice works best if there are numerous screens • Pilots prefer voice to be used for warning messages, but visual displays for everything else • But when continually engaged in a task, pilots respond faster to visual messages • Privacy • Security • Not disturbing others (offices)

  11. Voice output (synthesized or recorded) • Recorded speech • Excellent quality • Natural • Possible if only limited amount of different phrases • Hard to make changes later • we should get the same person to read new material • also recording conditions etc. should be similar • Each possible phrase should be recorded • combining material from different recordings sounds unnatural and unpleasant • Synthesized speech • Quality is still significantly worse than natural speech • Very flexible • Mature technology • Stable and reliable software available • Requires reasonable amount of resources • Cheap • Available for most of the (western) languages • Sometimes problems with text interpretation • At the moment the control over the speech is rather limited

  12. Speech Synthesis • Formant synthesis • based on acoustic features of speech: a set of filters is used to model natural speech sounds • intelligible, but not very pleasant (machine like) • Concatenating synthesis • speech is constructed by mixing short samples of recorded natural speech together • longer samples make more natural sounding speech but it is also harder to collect to samples • Acoustic modeling synthesis • models the vocal track and simulates how it works - very complex to compute even with simplified models • Prosody • prosody: volume, speed and pitch variations and pauses in speech • if speech has no prosody, it sound very monotonic and it’s hard to understand • synthesizers add basic prosody to speech • synthesizers don’t know where to put emphasis and complex sentences can cause problems • user can add simplex control tags to control speed, volume, pitch and pauses • this control is however very rough and works in word level

  13. Voice output (synthesized or recorded) • Quality and acceptance • In general, users do not prefer synthetic speech • Even unnatural mixture of natural and synthetic speech is sometimes better than than all synthetic • Some people have much more difficulties with synthesis than others • People learn to listen to synthetic speech • Many blind people who listen to a synthesizer daily can use it with very fast speaking rates • Recommendations • Avoid lengthy segments of voice output • The output is only communicated in real time (slower than reading) • It must be simple enough to be immediately understood or to fit in short term memory • Early parts of longer messages are forgotten • Use a normal output rate of 180 words per minute (wpm) • Allow experts to increase the rate to 240 wpm(Note that this is still slower than the average reader)

  14. Voice output (synthesized or recorded) • Recommendations • Allow users to easily • Request repetition of messages • Skip back a few seconds • Skip ahead once they have heard what they need • e.g. immediately choose the next action • Be aware of where to place key information in output sentences: • At end if output is highly variable • Users better remember the last few words. • e.g. temperature in weather reports • e.g. ‘Boss said meeting changed to 3 p.m.’ vs. ‘Meeting changed to 3 p.m. by the boss’ • At start if information is structured and user can skip ahead • Where the user knows what to listen for, speed becomes critical. • e.g. ‘3 messages in your mailbox’ • vs. ‘you have 3 messages’ • Place the required action after its description: • e.g. ‘To exit your mailbox, press 9’

  15. 14. Natural Language Interfaces • A company VP came to work and saw a message ‘Talk to me - end all messages by hitting return’. The VP thought the machine was connected to the engineer: • VP: Do you think I can use the computer this morning? • Resp: Why do you ask? • VP: I might be able to make some additional sales. • Resp: Why aren’t you sure? • VP: My prospective customers haven’t seen a demonstration. • Resp: Does this mean very much to you? • VP: Of course it does. • Resp: You seem very positive about that. • VP: This is ridiculous. • Resp: What do you mean this is ridiculous. • VP: Is there any reason why I can’t use the computer now? • Resp: Tell me more about your prospective customers. • VP: Damn it, call me at 491-1850

  16. 14. Natural Language Interfaces • When a system operates with an NL interface, users expect it to behave like a human: • Naive users will tend to think it ... • Can understand arbitrary grammar and vocabulary • Is ‘intelligent’. • An NL interface can be very confusing if certain rules are ignored • Rules of using NL • Avoid leading the user to think the system is more capable than it really is • If the system understands only a limited vocabulary, guide the user to use this.

  17. Rules of using NL • Respect implicit rules of human conversation • Use active voice (not passive). • e.g. Bad: The data was produced by X • e.g. Good: X produced the data • Be cooperative • Suggest alternatives when rejecting an input Or tell the user where to find alternatives. • Prioritize the alternatives • Correct or tolerate minor errors in pronunciation and grammar violations • Give meaningful responses • Avoid excessive use of simple ‘yes’ and ‘no’. • Avoid deluging the user with unwanted information. • But allow the user to dig deeper if she or he wants

  18. Rules of using NL • Rephrase the user’s input • Seek confirmation before taking any action • Always build in a ‘clarification’ mechanism • The user corrects a faulty system interpretation • ... or the system prompts for more detail • Avoid jargon and excessive familiarity or joking in the system. • Use a restricted natural language • Technology does not yet permit full NL • Use Wizard technique to find out the kinds of dialogs users will have with the machine • A software engineer provides the computer’s side of the dialogue • Beware that: • NL systems are very expensive to build • Many do not work well • They are hard to maintain and internationalize • They may be slower and harder to use than more artificial-looking interfaces

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