The Interaction

1. The Interaction IACT 403 IACT 931 CSCI 324 Human Computer Interface Lecturer: Gene Awyzio Room: 3.117 Phone: 4221 4090 Email: gene@uow.edu.au

2. Overview • Notion of interaction, interaction frameworks • Ergonomics • Interaction styles • Context of interaction

3. Interaction Frameworks • Interaction: the communication between theuserand the system • Why have a framework? • Allows contextualisation, presents a globalview

4. Terms of Interaction • Domain: Area of expertise and knowledge in real-world activity • Tasks: Operations to manipulate the concepts of a domain • Goal: Desired output from a performed task • Intention: Specific action required to meet goal. • Task Analysis: Identification of problem space for the user in terms of the domain, goals intentions and tasks.

5. Interaction Frameworks • Donald Norman’s Interaction framework • user establishes the goal • formulates intention • specifies actions at interface • executes action • perceives system state • interprets system state • evaluates system state with respect togoal

6. Interaction Frameworks • Some systems are harder to use than others • Gulf of Execution - user’s formulation ofactionsmay be different to those actionsallowed by thesystem • Gulf of Evaluation - user’s expectation of thechanged system state may be different to theactualpresentation of this state • Norman’s model concentrates on user’s view of theinterface only

7. O S U I Interaction Frameworks • Extended by Abowd and Beale:theirinteraction framework has 4 parts • User • Input • System • Output • Each has its own unique language. • Interactionnecessitates translation between languages

8. Interaction Frameworks • Problems in interaction occur whentranslationbetween one language and thenext is difficult, orimpossible. • User intentions translated into actions at theinterface, • Translated into alterations ofsystem state, • Which in turn are reflected inthe output display • Which is interpreted by the user.

9. Interaction Frameworks • These are general frameworks forunderstandinginteraction • not restricted to electronic computersystems • identifies all the major componentsinvolved ininteraction • allows comparative assessment ofsystems • an abstraction

10. Ergonomics • Study of the physical characteristics ofinteraction. • Also known as human factors. • Ergonomics good at defining standardsandguidelines for constraining the waywe design certainaspects of systems.

11. Ergonomic Considerations • Arrangement of controls and displays • e.g. controls grouped according to function, orfrequency of use, or sequentially • Surrounding environment • e.g. seatingarrangements adaptable to copewith allsizes of user

12. Ergonomic Considerations • Health issues • e.g. physical position, environmentalconditions (temperature, humidity),lighting,noise • Use of colour • e.g. use of red for warning, greenfor okay, • awareness of colour-blindnessetc.

13. Interaction styles • Interaction can be seen as a dialogue between thecomputer and the user. Some applications havevery distinct styles of interaction. • We can identify some common styles • command line interface • Menus • natural language • question/answer and query dialogue • form-fills and spreadsheets • WIMP

14. Command line interface • Way of expressing instructions to the computerdirectly • Can be function keys, single characters,short abbreviations, whole words, or a combination. • Suitable for repetitive tasks • Better for expert users than novices • Offer direct access to system functionality • Command names/abbreviations should bemeaningful • Typical example: the Unix system

15. Menus • Set of options displayed on the screen • Options visible so demand less recall • Rely onrecognition so names should bemeaningful • Selected by using mouse, numeric oralphabetickeys • Often options hierarchically grouped: • Sensiblegrouping is needed

16. Menus • Menu systems can • be purely text based, with options presented asnumbered choices, or • have graphical component, with menuappearing in box and choices made eitherby typinginitial letter, or moving aroundwith arrow keys • Restricted form of full WIMP system

17. Natural language • An attractive option: • Familiarspeech recognition or typed natural language can beused • Problems • Vague • Ambiguous • One solution • Try to understand a subset

18. Query interfaces • Question/answer interfaces - user is led throughinteraction via a series of questions. • Suitable for novice users but restricted functionality. • Often used in information systems. • Query languages (e.g. SQL) used to constructqueries to retrieve informationfrom database. • Effective use requires understanding of databasestructure and language syntax, hence requires someexpertise.

19. Form-filling interfaces • Primarily for data entry or data retrieval. • Screen like paper form. • Data put in relevant place. • Requires good design and obvious correctionfacilities.

20. Spreadsheets • VISICALC first (early 1980s) • Lotus 1-2-3, Excel common today • Sophisticated variation of form-filling: • grid of cells, each of which can contain a value or aformula • formula can involve values of other cells e.g. sumof all cells in this column • user can enter and alter data andspreadsheet willmaintain consistency and ensure formulae arecorrect

21. WIMP Interface • Windows • Icons • Menus • Pointers • (or windows, icons, mice, and pull-down menus) • Default style for majority of interactive computersystems today, especially PCs and desktopmachines

22. Windows • Areas of the screen that behave as if they wereindependent terminals • Can contain text or graphics • Can be moved or resized • Can overlap and obscure each other, or can be laidout next to one another (tiled) • Scrollbars allow the user to move the contents ofthe window up and down orfrom side to side • Title bars describe the name of the window

23. Windows • Icons • Small picture or image, used to represent someobject in the interface, often a window. • Windows canbe closed down to this small representation(iconised) allowing many windows to be accessible. • Icons can be many and various - highly stylized orrealistic representations.

24. Pointers • Important component, since WIMP style relies onpointing and selecting things such as icons andmenu items. • Usually achieved with mouse • Joystick, trackball, cursor keys or keyboardshortcuts are also used • wide variety

25. Menus • Choice of operations or services that can beperformed offered on the screen. • Required option selected with pointer

26. Menus • Problem - menus can take up a lot of screen space • Solution - use pull-down or pop-up menus • pull-down menus are dragged down from asingle title at the top of the screen • pop-up menus appear when a particularregion of the screen (maybe designatedby anicon) is clicked on • Some menus are pin-up menus - they stay on thescreen until explicitly requested to go away.

27. Menus • Anothertype is the fall-down menu - similar to the pull-down,but the bar doesn’t have to be explicitly selected. • Also cascading menus - one menu selection opensanother menu adjacent to it, and so on. • Pie menus - menu options arranged in a circle. • Easier to select item (larger target area) and quicker(same distance to any option)

28. Menus • Keyboard accelerators sometimes offered • keycombinations that have same effect as selecting themenu item • General problem: what to include in menus at all,and how to group items.

29. WIMP additions • Buttons - individual and isolated regions within adisplay that can be selected to invoke an action. • Radio buttons - set of mutually exclusivechoices • Check boxes - set of non-exclusive choices Check Boxes Buttons Radio Buttons

30. WIMP additions • Palettes - indicate the set of possible modesavailable, plus the current mode. • Usually acollection of tiled icons • Example: a drawing package may have a paletteindicating whether boxes, circles, lines or text arebeing drawn, another that indicates the set of fillpatterns available, and another thatindicates thecolours available

31. WIMP additions • Dialogue boxes - information windows that pop upto inform of some important event or request certaininformation. • Example: when saving a file, a dialogue box isdisplayed to allow the user to specify the filenameand location. Once the file is saved, the boxdisappears. • Collectively known as widgets • A particular style of drawing these widgets, and theirbehaviour when activated, makes up the look andfeel of an interface.

32. Social and Organizational Context • Interaction affected by social and organizationalcontext • Other people - desire to impress,competition, fearof failure • Motivation - fear, allegiance, ambition, self-satisfaction • Inadequate systems cause frustration and lack ofmotivation