9. Interaction Devices

1. 9. Interaction Devices • Keyboards and Keypads • Keyboard layouts • QWERTY layout (Christopher Latham Sholes), Dvorak layout, ABCDE style • number pads – telephone* layout and calculator layout • wrist and hand placement awkward • Keys • ½-inch-square keys (12 mm square), concave surface with a matte finish • 40- to 125-gram force and a displacement of 3 to 5 mm, tactile and audible feedback • larger for reliable access, locking by embedded light, labels, home keys (F and J) • Function keys, Cursor movement keys -- inverted T arrangement, auto-repeat feature • Keyboards and keypads for small devices • reduced, wireless, foldable, virtual keyboards, softkeys • tap on virtual keyboards, handwrite on a touch sensitive surface (Graffiti) • Pointing Devices • Pointing tasks • 6 types of interaction tasks -- Select, Position, Orient, Path, Quantify, Text • direct control (light pen, touchscreen, stylus) vs. indirect control (mouse, trackball, joystick, etc) • Direct-control pointing devices • lightpen – incorporate a button – arm fatigue, hands obscuring part of the screen, users removing hands from the keyboard, picking up the lightpen

2. touchscreen (fatigue, obscuring the screen, hand off keyboard, imprecise pointing, smudging of the display) – land-on strategy, lift-off strategy • pointing on the LCD surface – handwriting recognition, stylus • Indirect-control pointing devices • more cognitive processing and hand-eye coordination • mouse, trackball, joystick, trackpoint, touchpad, graphics tablet • Comparison of pointing devices • direct pointing devices – fastest but the least accurate devices • mouse for speed and accuracy, mouse was found to be faster than the trackpoint • users’ tasks matter – browsing, precision pointing • Fitts’ Law • the pointing time is a function of the distance and the width • well established for adults users • Novel devices • foot controls, eye-tracking (Midas touch problem), DataGlove • ubiquitous computing and tangible user interfaces • handheld devices • Speech and Auditory Interfaces • Discrete-word recognition • recognize individual words spoken by a specific person – 90-98% reliability for 100- to 10,000-word or larger vocabularies

3. speaker dependent training, speaker independent system • hands are busy: mobility required; eyes occupied:harsh or cramped conditions • recognition rate – background sounds change, user is ill or under stress, similar vocabulary • more demanding of working memory than the hand/eye coordination • Continuous-speech recognition • difficulty in recognizing the boundaries between spoken words • Voice information systems • Speech generation • synthesis – in some cases, removal of speech generation • Non-speech auditory interfaces • audio tones – confirmation for most users, vital for the impaired; after 2 hrs, distraction • auditory icons (familiar sounds), earcons • Displays – Small and Large • Display technology • CRT, LCDs, Plasma panel, LEDs, Electronic ink, Braille displays • Large displays • information wall displays (situation awareness), interactive wall displays, multiple desktop displays • Heads-up and helmet-mounted displays • Mobile device displays • poor readability

4. Animation, image, and video • digital photography, optical character recognition, videodisks, CD-ROMs, digital versatile disks (DVDs), motion picture experts group (MPEG), MP3 • Printers • thermal printers, dot-matrix printers, inkjet printers, impact-line printers, laser printers • plotters, photographic printers • braille embossers • three-dimensional printers

9. 10. Collaboration • Goals of Collaboration • collaboration by the goals and tasks of the participants: • Focused partnership – collaboration between two or three people; email, chat, instant messages, voice mail, telephone, video conferencing, SMS, photo exchanging • Lecture or demo – one person sharing info with many users at remote sites; the start time and duration is the same for all; no history keeping • Conferences – groups communicate at the same time or spread out over time, but with participants distributed in space; a record of previous conversation, blogs, wikis • Structured work processes – let people with distinct organization roles collaborate on some task • Electronic Commerce – negotiations can be distributed in time and space • Meeting and decision support – face-to-face meeting with simultaneous contributions; anonymity • Electronic commerce – customers browsing and comparing prices, accurate recording and rapid dissemination of results • Teledemocracy – produce consensus through online conferences, debates, and votes • online communities – communities of interest (Cols), communities of practice (CoPs), networked communities • collaboratories • telepresence – immersive SD VR • time-space matrix (Ellis et al., 1991)

10. Asynchronous Distributed Interfaces: Different Place, Different Time • Electronic Mail • Newsgroups, listservers, discussion boards, conferences, blogs, and wikis • newsgroups – organized into hierarchies to help users to find topics of interest • listserv –individuals must subscribe to receive email notices online conference • discussion board – evolved from bulletin board • web-logs (blogs) • wikis – collaborative web pages that are open for anyone to add or revise content • online magazines, newsletters, journals • Online and networked communities • topically focused and geographically dispersed • shared goal, identity, or common interest and participate on a continuing basis • Synchronous Distributed Interfaces: Different Place, Same Time • Chat, instant messaging, and texting • Audio and video conferencing • video conferencing, DTVC (desktop videoconferencing) – slow response time, background noise, inappropriate lighting, eye contact difficulty, small image size, privacy invasion, jerky motion

11. Face to Face Interfaces: Same Place, Same Time • Electronic meeting rooms, control rooms, and public spaces • brainstorming, voting, and ranking • parallel communication, anonymity, group memory, process structure, task support and structure • Electronic classrooms

12. 11. Quality of Service • Introduction • quality of service – time is precious; harmful mistakes should be avoided; reduce user frustration • focus on the decisions to be made by network designers and operators • Models of Response-Time Impacts • response time – the number of seconds it takes from the moment users initiate an activity until the computer begins to present results o the display or printer • lengthy (> 15 sec) response time – ↓ productivity,↑error rate, ↓satisfaction • more rapid (< 1 sec) – ↑ productivity, ↑ error rate for complex tasks • display rate – the speed, in characters per second (cps), at which characters appear for the user to read – graphics in bytes per seconds • cognitive model of human performance in response time useful in making predictions, designing interfaces, formulating management policies • Robert B. Miller’s review (1968) – 17 situations where response time differ but the principle of closure, short-term memory limitations, and chunking still apply • Limitations of short-term and working memory • George Miller (1956) – “the magical number seven – plus or minus two”  seven chunks of info. in working memory for 15 to 30 seconds – familiarity

13. STM processes perceptual input, whereas WM is used to generate and implement solutions • Highly volatile, disruptions cause loss in info, delays can require that the memory be refreshed • Sources of errors • interference, delay – preferred response time • long response time leads to wasted effort and more errors because a solution plan is reviewed repeatedly • short response times may generate a faster pace in which solution plans are prepared hastily and incompletely • Conditions for optimum problem solving • Wickelgren (1977) -- speed-accuracy tradeoffs • feedback -- graphical dynamic progress indicators • Expectations and Attitudes • acceptable response time – 2-second limit • previous experience • individual’stolerance for delays • task complexity and the user’s familiarity with the task • longer response time – web-page content less interesting, lower in quality, negative user perception of the companies • three conjectures

14. User Productivity • The nature of the task influence on changes in response time alter user productivity • With shorter system response times – works more quickly but decisions less than optimal • with a data-entry task, three strategies on the response time • RT<1 sec, worked automatically without checking for the next data value • RT>2, monitored the display carefully • In between, users paced themselves • users will adapt their work style to the response time • Variability in Response Time • Extreme variation in response time is unsettling and should be prevented or acknowledged • The effect of modest variations in response time • people detect 8-percent changes in a 2 or 4 sec response time  a fixed short response time not for all actions but for classes of actions • modest variations in response time do not severely affect performance (adapting) butextreme variation should be prevented or acknowledged by the interface • With shorter RT, hasty decision; with longer RT, frustration of waiting burdened STM • physiological effect of response time  higher error rates, higher systolic blood pressure, more pronounced pain symptoms with shorter response time • Frustrating Experiences • major sources of problems – web browsing, e-mail, word processing • interface redesign, software quality improvement, network reliability increases • increased learning, careful use of services, self-control of their attitudes • spam, viruses

16. 12. Balancing Function and Fashion • Error Messages • lack of knowledge, incorrect understanding, inadvertent slips • Specificity • Constructive guidance and positive tone • what uses need to do to set things right • User-centered phrasing • Appropriate physical format • mixed uppercase and lowercase messages • optimal placement – proximity, consistent place (the bottom line), dialog box not obscuring the problem • alarm – users control • Development of effective messages • upgrade performance and greater job satisfaction • Nonanthropomorphic Design • may give users an erroneous model of how computers work and the machine’s capacities • to clarify the differences between people and computers • an anthropomorphic interface can be distracting or produce anxiety for others • Walker, Sproull, & Subramani (1994) – “incautiously adding human characteristics like face, voice, and facial expressions could make the experience for users worse than better” • external locus of control by animated characters – increase anxiety and reduce performance • use of first-person pronouns – deceive, mislead, confuse users • Interfaces should neither compliment nor condemn users, just comprehensible feedback

17. Display Design • dense or cluttered displays can provoke anger, and inconsistent formats can inhibit performance • Field layout • Empirical results • data label, clustering related info, appropriate indentation and underlining  improve performance • consistent location, structure, terminology, sequence of displays • Display-complexity metrics • four task-independent metrics for alphanumeric displays (Tullis, 1997) • overall density, local density, grouping, layout complexity • displays that optimize search times do not necessarily optimize subjective ratings • fast performance  grouping of items; high subjective ratings  low local density and low layout complexity • effective display design – 6 to 15 groups neatly laid out, surrounded by blanks, similarly structured • web-based designs were dramatically different – cool designs, hot images, attention-grabbing layouts  user preference • more accurate prediction of user performance – integrating with task frequencies and sequences  layout appropriateness deal with buttons, boxes, lists • Window Design • Coordinating multiple windows • coordinated windows – windows appear, change contents, and close as a direct result of user actions in the task domain • coordination – a task concept that describe how information objects change based on user actions

18. Synchronized scrolling  Hierarchical browsing • opening/closing windows  Saving/opening window state • Image Browsing • overview and detailed view -- zoom factor 5-30 effective (additional intermediate view) • side-by-side placement, zoom-and-replace approach • fisheye views – magnified focus area while preserving the context in a single display • visually appealing, even compelling • but changing distortion may be disorienting and zoom factor never exceeds 5 • Color • use color conservatively • limit the number of colors • recognize the power of color as a coding technique • ensure that color coding supports the task • have color coding appear with minimal user effort • place color coding under user control • design for monochrome first • consider the needs of color-deficient users • use color to help in formatting • be consistent in color coding • be alert to common expectations about color codes • be alert to problems with color pairings • use color changes to indicate status changes • use color in graphic displays for greater information density

20. 14. Information Search and Visualization • Introduction • information retrieval  information gathering, seeking, filtering, or visualization • database management  data mining from data warehouses and data marts  knowledge networks or semantic webs • information search using traditional UI – hurdle for novice users and an inadequate for experts • task objects are represented by interface objects in structured relational databases, textual document libraries, or multimedia document libraries • task actions (browsing or searching) represented by interface actions (scrolling, zooming, joining, or linking • Tasks – specific/extended fact finding, exploration of availability, open-ended browsing and problem analysis • Searching in Textual Documents and Database Querying • SQL – requires training, and even then users make frequent errors • natural-language queries – appealing but limited computer processing capacity • form-fillin queries and query-by-example • five-phase framework • Formulation: expressing the search  source, fields, phrases, variants • Initiation of action: launching the search  explicit, implicit initiation, dynamic query • Review of results: reading messages and outcomes  sequence and cluster • Refinement: formulating the next step  history buffer • Use: compiling or disseminating insight

21. Multimedia Document Searches • image search -- query by image content (QBIC)  search for distinctive features or search for distinctive colors • Map search – search by features • Design or diagram search • Sound search • Video search • Animation search • Advanced Filtering and Search Interfaces • filtering with complex Boolean queries • automatic filtering • dynamic queries • faceted metadata search • collaborative filtering • multilingual searches • visual searches • Information Visualization • the use of interactive visual representations of abstract data to amplify cognition • visual-information-seeking mantra – overview first, zoom and filter, then details on demand • Data type by task taxonomy (TTT) and seven tasks (Box 14.2)

22. 1-D 1inear data • in a sequential manner – textual documents, dictionaries, alphabetical list of names • interface-design issues include what fonts, color, size to use, and what overview, scrolling, or selection methods to provide for users • 2-D map data • maps, floor plans, newspaper layouts • interface-domain features (size, color, opacity) • user tasks – to find adjacent items, regions containing items, paths between items and to perform the seven basic tasks • 3-D world data • molecules, the human body, and buildings • users’ tasks typically deal with continuous variables such as temperature or density • cope with the position and orientation when viewing the objects  potential problems of occlusion and navigation  overviews, landmarks, teleoperation, multiple views and TUI • Multidimensional data • n attributes in a n-dimensional space (dynamic two-dimensional scattergram) • tasks include finding patterns, clusters, correlations, gaps and outliers • three-dimensional scattergram (disorientation and occlusion) • Temporal data • items have a start and finish time, and that items may overlap • finding all events before, after, or during time period and the seven basic tasks

23. Tree data • Network data • shortest or least costly paths connecting two items or traversing the entire network • Overview task • movable field-of-view box (zoom factors of 3 to 30), fisheye strategy • Zoom task • Filter task • Details-on-demand task • simply click on an item to get a pop-up window with values of each of the attributes • Relate task • proximity, containment, connection, color coding; highlighting • History task • history of actions to support undo, replay, and progressive refinement • Extract task • Challenges for information visualization