Interaction Design-2
Contents
1. 1 sait l i 1 Les 4 5 6 8 9 10 11 12 Trials Trials session 1 session 2 Barnard Hammond MacLean and Morten 1981 Learning and remembering interactive commands Proceedings Human Factors in Computing Systems pp 2 7 34 49 Command language syntax design Poor VolB FileA D FileA VolB ER L KO M Rauterberg TU e Improved OR s filea volb o filea volb lal KO Source Mayhew 1992 chap 7 search for filea in volb open filea in volb list all lines with KO 35 49 Command name abbreviation design 1 1 M Rauterberg TU e Truncation Vowel deletion Contraction Minimum to distinguish Phonetic First syllable User created append execute append execute append execute translate transfer append execute append execute APPE EXEC APPND EXCT APND EXTE TRANS TRANF APND XQT APPN EXEC by individuals Source Mayhew 1992 chap 7 36 49 Command name abbreviation design 2 M Rauterberg TU e Name Move forward Move backward Insert Delete Replace Search Delete Send Print Search Send Find Choose Abbreviations Poor Improved MovF MovF Mvb MovB I Ins Di Del Repl Rep Srch Sea x Del Sn Sen Prt Pri Srch Sea Sn Sen Fi Fin Ch Cho Source Mayhew 1992 chap 7 37 49 Command name abbreviation design 3 Source Mayhew 1992 ch2. 75 M Rauterberg TU e Advance retreat Right left Straighten bend Swing out swing in Release take 1 63 2 13 1 25 Move robot forward change robot backward Change robot right move robot left Change robot up move robot down Change arm right move arm left Change arm open move arm close 1 81 4 25 4 63 Go back Turn left Up bend Pivot sweep Unhook grab 2 73 1 63 2 38 taken from Caroll 1982 Learning using and designing filenames and command paradigms Behaviour amp Information Technology Vol 1 4 327 346 32 49 Command name design 2 task completed novice task completed familiar task completed expert erroneous commands novice erroneous commands familiar erroneous commands expert Notational English like Find tooth 1 Backward to tooth List 10 List 10 lines List ko List all lines with ko 1 ko lalw ko 28 42 43 62 74 84 19 0 11 0 18 0 6 4 9 9 5 6 taken from Ledgard Whiteside Singer and Seymor 1980 The natural language of interactive systems Communications of the ACM vol 23 556 563 M Rauterberg TU e 33 49 Command name design 3 Specific General Fetch Transfer Send Put Front Move Insert Add Rubout Edit Split Open M Rauterberg TU e Help 6 requests per I General names e Specific names trial e 2 o ll 1 1
3. M Rauterberg TU e 5 49 The function form mapping implemented I fi unctions i perceivable user interface forms intended semantic perceived semantic DMM designer s mental model UMM users mental model M Rauterberg TU e 6 49 The three important mappings User s world device pixel world semantic D function 1 function 2 function 3 function n M Rauterberg TU e 7 49 The hardware control pixel world mapping 2 Input devices are the hardware components you use to talk to a computer You use them to place requests send messages to the computer or to other people move around in virtual worlds or even shoot at enemies in some computer games A few examples of commonly used input devices are Computer keyboard eJoystick Microphone eMouse ePen some with some without a pad lt Touch sensitive screen eTrackball eTrackPoint M Rauterberg TU e The hardware control pixel world mapping 2 Mouse Advantage Moves cursor around the screen faster than using keystrokes Disadvantage Requires moving hand from keyboard to mouse and back Repeated motion can lead to carpal tunnel syndrome e Trackball Advantage Does not need as much desk space as a mouse Is not as tiring since less motion is needed Disadvantage Requires fine control of the ball with just one finger or t
4. c M Rauterberg TU e 25 49 Syntactical structure 2 e Syntax appropriateness for modality the syntax structure of the command phrases should be appropriate for the input modality e g voice typed input gestures EXAMPLE voice input is used exclusively and the syntax is completely consistent with spoken language consistency with modality syntax should be consistent within a given modality EXAMPLE for a screen based command dialogue the object follows the action e g action object syntax throughout the application consistency across modalities syntax should be consistent across modalities as much as possible EXAMPLE voice is used as well as typed input for commands in an application and the syntax is object action for both modalities e Command separation if the input of multiple commands is allowed a simple and consistent method to separate commands should be used EXAMPLE BLANKS if system constrains do not require the use of a specific separator BLANKS should be used rather than punctuation marks to separate commands EXAMPLE STANDARD SYMBOL if system constrains require a separator other than BLANKS to distinguish separate stacked commands a simple STANDRAD SYMBOL should be used consistently e g using the slash in the sequence of commands words sort format print M Rauterberg TU e 26 49 Syntactical structure 3 Language compatibility command structure sema
5. provided depicting command characteristics e g name function syntax parameters abbreviations hot key function key assignment EXAMPLE using a keyboard template to depict function key assignments for commands or using a quick reference card to list all available commands and associated information e Long argument lists if a command has long list of arguments and associated parameters the use of additional dialogue techniques should be provided EXAMPLE for a command language with numerous arguments the user can access a dialogue box that has a list with parameter values that can be selected for each command argument M Rauterberg TU e 42 49 How to describe a CL Meta Syntax CL Syntax non terminal symbols Commands terminal symbols M Rauterberg TU e Content Syntax to describe the syntax of the command language with meta symbols Syntax of the command language major distinction between non terminal and terminal symbols List of all specified commands Examples Backus Naur Form BNF Syntax diagram State transition net Written text lt Command gt lt name gt lt argument gt lt parameter gt lt name gt cancel print list cancel print filename list commands 43 49 What is a meta syntax A meta syntax is described e g in Backus Naur Form BNF BNF was first used by John Backus and Peter Naur to describe Algol in 1963 It consists of a set of
6. 4 e FLAT vs DEEP structure a flat CL has lots of commands at every level whereas a deep CL has a few basic commands which put the system into a level of input mode at which it will recognize certain commands Advantage of a flat CLs is that they are very powerful very complex command sequences can be expressed by stringing the right commands together but require users to remember lots of command words e g UNIX POSITIONAL vs KEYWORD positional CLs have a strict syntax the order in which command words are issued contains information e g UNIX command mv filename directoryname For CLs which recognize keywords the user can string commands together in any order if there is potential ambiguity the system will query ask for confirmation before executing a command e MNEMONICS most CLs use abbreviated natural language words as commands to facilitate recall e g mkdir for make directory M Rauterberg TU e 28 49 Command representation 1 e Command names general command names should be easily related to their function generally stated as verbs usually in imperative form be easily remembered by users and be consistent with the user s task requirements experience and language usage distinctiveness a command names should be distinctive b command names should be avoided that look or sound similar but have different meanings c if command operations have inverse or counterparts congruent pairs of comm
7. Interaction Design 2 Command Language Matthias Rauterberg Faculty Industrial Design Technical University Eindhoven g w m rauterberg tue nl 24 NOV 2006 Key references literature 1 D Norman 1988 The psychology of everyday things Basic Books chapter 1 D J Mayhew 1992 Principles and guidelines in Software User Interface Design Prentice Hall chapter introduction chapter 12 input and output devices J Preece Y Rogers H Sharp 2002 Interaction design beyond human computer interaction John Wiley amp Sons chapter 1 what is interaction design chapter 2 understanding and conceptualizing interaction M Rauterberg TU e 2 49 Key references literature 2 D J Mayhew 1992 Principles and guidelines in software user interface design Prentice Hall chapter 7 dialog styles command language chapter 6 dialog styles question and answer chapter 17 user documentation ISO FDIS 9241 1997 Ergonomic requirements for office work with visual display terminals VDTs Part 15 command dialogues C M Brown 1989 Human computer interface design guidelines Ablex Publ Chapter 3 effective wording M Rauterberg TU e 3 49 What is User System Interaction about Working domain Goal Actual Performance gt Desired Performance Working system system M Rauterberg TU e 4 49 Interface Design or Interaction Design Meron user interaction system
8. ands for these operations should be provided EXAMPLE a in English the words insert and delete are more semantically distinct than add and remove i e add and remove typically have many different interpretations EXAMPLE b use replace rather than change EXAMPLE b in English store and restore should be avoided because they have different meanings but sound similar EXAMPLE c read write open close yes no user orientation command names should be chosen that are consistent with the user s experience and correspond to the user s operational language NOTE if there are multiple user groups it may be important to provide different sets of command names for these different groups emotional content words selected as command words should be emotionally neutral EXAMPLE in English use cancel instead of abort and use delete rather than kill command word length if command input is typed command words should be not exceed 7 characters suffixes and prefixes command word should not incorporate unnecessary suffixes or prefixes EXAMPLE in English delete rather than deleting deleted or deletes M Rauterberg TU e 29 49 Command representation 2 e Abbreviations general if users must type commands they should be able to use abbreviations instead of typing complete commands If it is appropriate to the task to provide command abbreviations these abbreviations should be obvious to the user easily remembered and faci
9. ap 7 M Rauterberg TU e Poor Names Next page Previous page Home Next document Previous document First document Screen print Print document Mailit Request Help Time Full Short Location Sclect services Exit Modify New search Change drawer Change cabinet NP PP H ND PD FD SH LO SS EX NS CD CC Improved Abbreviations Next page NP Previous page PP First page FP Next document ND Previous document PD First document FD Print screen PS Print document n Print result PR Display request DR Display help DH Display time DT Format full FF Format short FS Format location FL Scleet services SS Exit services ES Modify request MR Change request CR Change drawer CD Change cabinet CC 38 49 Input and output considerations 1 General users should be in control of the dialogue at all times be able to easily recover from errors and not be required to input more information than is necessary for successful task performance Command reuse if the same sets of commands are used repeatedly during a work session the system should provide a way of reusing the commands without requiring the user to type them again EXAMPLE giving users a command history list from which they can select a previously used command Command queuing users should be provided with the capability to key in a series of commands command queuing or stacking rather than wait for the system to execute each i
10. ate e g wheel control on mouse Surface 2D Possible Appropriate e g mouse button for selection e g pen for handwriting painting Space 3D NOT appropriate Appropriate e g dataglove datasuite M Rauterberg TU e 10 49 Pros and Cons of Pointing Devices Cursor Mouse Joy stick Trackball Touch Touch pad keys screen Speed Slow Fast Medium Medium Fast medium Accuracy High Medium Medium High Low Medium Speed Some Yes Some Yes Yes Yes control Continuous No Yes Soe Yes Yes Yes movement Fatigue Low Medium Medium Medium High Medium Directness Direction Direction Direction Direction Direction Direction distance speed distance distance speed speed speed Best uses Cursor Cursor Cursor Cursor Point Point select point point point select select select select track draw track drag drag M Rauterberg TU e 11 49 DIN 66 234 EC directive ISO 9241 Ulich part 8 90 270 EEC part 10 1988 1990 1996 1991 suitability for the task self descriptiveness conformity with user expectations controllability error robustness suitability activity adapted feeback about system states appropriate format and pace of information presentation information and instruction of user ease of use applicable to skill level hearing and participation of users suitability for the task task orientation self descriptiveness transparency feedback conformitity with us
11. commands and command macros and they should be able to revert back to the default names when desired Echoing typed commands a the user s input should be displayed echoed in a consistent position b typed in command characters should be displayed echoed as the user types each character EXAMPLE a displayed on a command line at the bottom of the screen or displayed after the prompt on the screen Output control if appropriate to the task and system constrains allow the command phrase should allow arguments for redirecting output interrupting output or stopping output Consistent output format commands resulting in similar or related output should present their resulting data in a consistent format EXAMPLE use of a single presentation format for lists of files processes directories etc M Rauterberg TU e 40 49 Feedback and Help 1 feedback and help should be provide users with information allowing them to control the dialogue recognise and recover from errors and determine their next course of action Command processing completion the system should indicate that the command processing has been completed by displaying the output resulting from the command and or prompt for the next command NOTE the feedback should be provide within 2 seconds intermediate feedback if the command processing is expected to continue for a longer period more than 5 seconds visual feedback indicating that the process
12. eclaration gt lt method modifiers gt lt result type gt lt method declarator gt lt throws gt lt method body gt lt method modifiers gt lt method modifier gt lt method modifiers gt lt method modifier gt may be written lt method modifiers gt lt method modifier gt lt method modifier gt public protected private static abstract final synchronized native M Rauterberg TU e 46 49 How to define a command language The command language SIMPLE can be defined by using EBNF Here is the definition of the syntax of SIMPLE plus commands defined with EBNF lt simple gt lt prompt gt lt command gt lt command_separator gt lt command gt lt command gt lt command_name gt lt argument gt lt parameter gt lt argument gt lt letter gt lt letter gt lt digit gt lt parameter gt lt letter gt lt letter gt lt digit gt lt prompt gt SIMPLE lt command_separator gt lt command_name gt CANCEL CA UNDO UN WRITE WR COPY CO DELETE DE WRITE f ename ength COPY nput filename copies output filename You can copy this general syntax definition and adapt it to your specific command language with your specific set of commands You do not have to use different colors M Rauterberg TU e 47 49 When to use CLs e User characteristics positive attitude high motiva
13. er compatibility expectations consistency suitability for learning support suitability for individualization controllability error tolerance selection possibilities user definability participation flexibility M Rauterberg TU e source EU Directive 90 270 source Ulich et al 1991 12 49 The interface architecture application manager F wy in eppen cat i dialog C ri i o manager dialog manager socio technical system source Rauterberg 1995 p 17 M Rauterberg TU e 13 49 Three different function types Secondary functions dialog manager Tertiary functions dialog Primary functions manager application manager Application object s M Rauterberg TU e 14 49 The function space function space FS perceptual functions PF hidden functions HF PFs of the PFs of the HFs of the HFs of the dialog application dialog application manager manager manager manager PDF PAF HDF HAF set of all possible function representations RF source Rauterberg 1995 M Rauterberg TU e 15 49 What is the state of the art e Known interaction styles command language menu desktop direct manipulation M Rauterberg TU e 16 49 What comes in the future e New interaction styles speech input output computer vision based inp
14. humb Repeated motions of the same muscles is tiring and can cause carpal tunnel syndrome e Glidepad Advantage Does not need as much desk space as a mouse Can readily be built into the keyboard Has finer resolution That is to achieve the same cursor movement onscreen takes less movement of the finger on the glidepad than it does mouse movement Can use either buttons or taps of the pad for clicking Disadvantage The hand tires faster than with a mouse since there is no support Some people don t find the motion as natural as a mouse e Pen Advantage Can use handwriting instead of typing Can use gestures instead of typing commands small size Disadvantage Must train device to recognize handwriting Must learn gestures or train device to recognize the ones you create Can lose the pen which is not usually attached to the device e Touchscreen Advantage It s natural to do reach out and touch something Disadvantage It s tiring if many choices must be made It takes a lot of screen space for each choice since fingers are bigger than cursors e Graphic tablet Advantage Don t have to redraw graphics already created Disadvantage Expensive taken from http www jegsworks com Lessons lesson3 lesson3 3 htm M Rauterberg TU e 9 49 9 The hardware control pixel world mapping 3 Nature of function discrete continuous button Appropriate NOT appropriate e g Cursor keys Linear 1D possible Appropri
15. ion dialogues Part 17 Form fill in dialogues D Mayhew Priniples and guidelines in software user interface design Prentice 1992 About usability evaluation methods J Dumas J Redish A practical guide to usability testing Ablex 1993 D Freedman G Weinberg Walkthroughs Inspections and technical reviews Dorset 1990 ISO 9241 Part 11 Guidance on usability Part 13 User guidance A Monk P Wright J Haber L Davenport Improving your Human Computer Interface a practical technique Prentice Hall 1993 J Nielsen R Mack ed Usability inspection methods Wiley 1994 About Design D Norman The psychology of everyday things Basic Books 1988 M Rauterberg TU e 49 49
16. is continuing should be provided to the user EXAMPLE hourglass with and time running out repeatedly displaying a message working NOTE it may be appropriate to provide such information earlier processing status if appropriate to the task and system constrains allow user should be provided with feedback concerning the relative amount of time remaining to complete the process EXAMPLE a status bar is shown indicating the amount of processing completed Error feedback timing error feedback should be provided after the full command including associated parameters has been entered rather than as soon as the error is discovered by the system EXAMPLE the user misspells the command print by pressing the t key rather than r key and the system indicates the mistake after the entire command has been entered and not before highlighting the unacceptable portion of the command should be highlighted in the context of the full command or a logical part thereof EXAMPLE the error portion might be highlighted by using reverse video or different colour M Rauterberg TU e 41 49 Feedback and Help 2 e Command information if appropriate to the task the user should be provided on request with information on commands available and their meaning appropriate syntax structure required and optional arguments available especially if the number is large command entry history e Performance aids performance aids should be
17. litate command input NOTE if the command input is an abbreviation and system constrains allow the whole command name may be displayed prior to or simultaneous with execution especially during learning the CL abbreviations rules a if command names are shortened they should be shortened using as simple a rule as possible that rule should apply to all commands and those arguments that can be abbreviated b if the task requires the user to generate and remember commands simple truncation should be used to shorten commands EXAMPLE a truncation pr for print dropping of vowels prnt for print EXAMPLE b to drop off characters beyond those necessary to keep the command unique e g q for quit qui for quit and que for query M Rauterberg TU e 30 49 Command representation 3 Function keys and hot keys general if function keys or hot keys are used for command input their use should be obvious to users or the key assignments should be readily accessible and these assignments should be consistent throughout the application application NOTE consider using function keys and hot keys for frequently used commands or when it is important to speed up command entry function key consistency function key assignments for commands should be consistent across related tasks within an application particularly for generic commands like help hot key consistency hot keys should have the same meaning throughou
18. lt digit gt lt quoted symbol gt lt letter gt lt digit gt lt symbol gt lt letter gt a b o z p lt digit gt 0 4 2 1 9 lt symbol 1 gt lt lt symbol 2 gt gt lt symbol 3 gt lt symbol gt TTL All blue items are meta symbols all red items are non terminals to describe the syntactical structure and all black items are terminals atomic building blocks BNF is not only important to describe syntax rules using non terminals and terminals but it is also very commonly used with variants e g EBNF by syntactic tools M Rauterberg TU e 45 49 EBNF is another meta syntax A meta syntax described in Extended Backus Naur Form EBNF see also UNIX as a concrete example The following meta symbols are added to BNF to describe the syntax of a programming language relies heavily on recursion to provide lists of items EBNF uses these extensions 1 Parentheses lt item1 gt lt item2 gt are used for grouping of items 2 lt item gt or lt item gt means item is optional 3 lt item gt or lt item gt means to take zero or more occurrences of item 4 lt item gt means to take one or more occurrences of item 6 Bold item means terminal symbol of the defined syntax 7 Italic item means placeholder or variable to be filled in later in the concrete context of use Example lt method d
19. n wikipedia org wiki Grammar e User Manual Handbook PDF e Meta Syntax of a Natural Language Description e Etc etc etc M Rauterberg TU e 20 49 Command language interface the normal view of MS DOS lt c gt 2 PO perceivable object PF perceivable function point DC dialogue context source Rauterberg 1995 M Rauterberg TU e 21 49 Command language interaction ey o HAFIP functional interaction point of sae i o interface the application manager representation space of function 1 the dialog and application objects PDO PAO a function 2 afunctions the representational CZ a function 4 interaction point PF PDFIP PAFIP atunction s a function 6 HDFIP li e functional application interaction point of the manager dialog manager jan as ass asa dialog manager M Rauterberg TU e 22 49 Basic definitions 1 Command C whole word text string abbreviation or string of words representing actions requested of the system Argument A independent variable including object used in a command phrase to modify or direct the action of a command NOTE arguments often include parameters Command language CL command set s phrases structure and syntax associated with a specific interaction of a user with a system by means of commands Command language structu
20. ndividual command NOTE separators should be provided to separate command strings see above under separators Error correction if errors occur re entry or editing should be required preferably for the erroneous portion of the command and associated parameters Editing a users should be allowed to edit commands prior to execution b if the application has a text editor the same text editing conventions used in the text editor should be apply to command dialogue editing Misspelling if appropriate for the task and system constrains allow the system should provide for interpretation and acceptance of misspelled commands unless there is ambiguity as to what command was intended M Rauterberg TU e 39 49 Input and output considerations 2 Defaults defaults should be provided to minimise typing requirements and to facilitate learning EXAMPLE if the disk drive is not identified it is assumed to be the currently set default drive NOTE arguments that have default parameter values are often referred to as optional arguments Destructive commands a if a command may have unintentional or destructive consequences e g delete a file the user should be allowed to cancel or undo the previous last command and its effects b the user should be required to confirm the intention of the command before command execution Customisation if system constrains allow users should have the capability to designate and use synonyms for
21. ntactical structure 1 e General The CL should be designed such that users enter Cs in a manner which is natural or famliar to the user without concern for how the system will process the Cs to produce the output e g the CL should reflect the user s needs rather than the system process and the syntax structure should be be consistent with user expectations task requirements and input devices Internal consistency The CL should be internally consistent so Cs with the same name function in the same way throughout the application regardless of the context Cs that do the same thing should have the same name e Macros If sequences of command words or command phrases are used frequently users should be allowed to create and use higher level commands macros for these sequences NOTE macros should follow the same recommendations as commands e Argument structure Command phrases should be be structured to minimize the complexity of arguments Long Lists if arguments are long more than 8 arguments then additional command names should be created functions should be combined under single arguments or lists should be broken into some logical functional groupings Dependencies dependencies between arguments of a command should be not dramatically change the meaning of the command phrase e g command quit filename to save data to the file named filename command cancel to cancel without saving instead of the more complex quit
22. ntics and syntax should correspond to the terminology and data organisation familiar or natural to the user EXAMPLE the rules for natural language syntax e g English French etc are applied in designing a query language e Command arguments command arguments should be easy for the user to specify and to relate to the commands that they modify NOTE in some cases it may be appropriate to represent arguments as names rather than single letters command elements linkage the command dialogue should be structured so that the relationship between the command phrase elements is clear arguments format if appropriate to the task keyword format parameter designated by argument identifiers that precede them should be used rather than positional formats parameter designated by their sequential position in the argument string following the command EXAMPLE keyword format change shape round colour red size 4 EXAMPLE positional format change round red 4 placement of optional argument if keyword format is used optional arguments should be placed at the end of the argument list Separation of arguments a if BLANK spaces are allowed a variable number of blanks should be allowed between command elements b if other separators are used a simple standard symbol should be used consistently EXAMPLE using the comma in the command phrase print fileA fileB fileC M Rauterberg TU e 27 49 Syntactical structure
23. re logical structure of the command dialogue and associated phrases Command phrase phrase including the command words or their abbreviations and associated separators and arguments with parameters Command set all available commands to the user to perform a given task in a particular application context Command syntax sequential and other procedural requirements for inputting the components into command phrases M Rauterberg TU e 23 49 Basic definitions 2 Command word name word or name used as a command in the command dialogue and representing actions requested from the system Command word abbreviation shortened version of a command word which is recognizable by the system as representing the command Hot keys keys other than numbered function keys e g F1 F2 etc not normally used for data entry such as modifier keys e g CRTL ALT or key combinations e g CRTL c which execute immediately without the need for any additional operations Keyword word in a command phrase identifying a particular argument class e g type font Modifier argument that alters or limits the action of a command Parameter value used in conjunction with a keyword to modify the action of a command or argument Separator string of one or more characters or a pause for voice input used to separate or organize elements in the command phrase and between command phrases M Rauterberg TU e 24 49 Sy
24. rules or productions of the form lt syntactic category gt a sequence of terminals syntactic categories and the symbol Definition of all used meta symbols x means is defined as juxtaposition means concatenation means alternation the logical exclusive OR optional items are enclosed in meta symbols and repetitive items zero or more times are enclosed in meta symbols and parentheses merely serve for grouping i e a b c stands for ac bc non terminals terminals M Rauterberg TU e are necessary to describe the syntactical structure and are surrounded by meta symbols lt and gt describe the atomic operations e g commands terminals of only one character are surrounded by quotes a 44 49 BNF is a meta syntax Now as an example maybe not the easiest to read but the different colors help here is the definition of the syntax of BNF expressed in BNF see also Wirth s BNF lt bnf syntax gt lt bnf rule gt lt bnf rule gt lt symbol 1 gt lt identifier gt lt symbol 2 gt lt symbol 3 gt lt expression gt lt expression lt term gt lt term gt lt term gt lt factor gt lt factor gt lt factor gt lt identifier gt lt quoted symbol gt lt expression gt lt expression gt lt expression gt lt identifier gt lt letter gt lt letter gt
25. t the whole application NOTE if commands can be accessed by menu as well as typing the hot key assignments should be the same as the accelerators used in the menus EXAMPLE ALT c is used for cancel and it is used consistently to provide that action throughout the consistent grouping of modifiers if modifier keys e g CRTL or ALT keys are used with other keys there should be a consistent rule of the modifier key usage EXAMPLE ALT letter keys is used for navigation and window manipulation and CRTL other letter keys is used for data manipulation imited modifiers multiple simultaneous modifier keys should be used in hot keys only if there are more commands than can be accommodated meaningfully by single modifier keys EXAMPLE in a dialogue ALT p rather than ALT CRTL p is used to issue a print command NOTE if possible use letter keys that are mnemonic in combination with modifiers it may be desirable to require the depression of more than one modifier key to reduce the possibility of accidentally causing a destructive action M Rauterberg TU e 31 49 Command name design 1 Congruent Hierarchical Congruent Non hierarchical Non congruent Hierarchical Non congruent Non hierarchical Move robot forward move robot backward Move robot right move robot left Move robot up move robot down Move arm right move arm left Change arm open change arm closed Rating 1 86 Errors 1 0 50 Errors 2 0
26. tion Knowledge and expertise moderate to high typing skills high system experiences high task experiences high application experiences infrequent use of other interaction styles high computer literacy e Job and task characteristics high frequency of use formal training mandatory use low turnover rate high task importance low task structure M Rauterberg TU e 48 49 About HCI in general L Barfield The user interface concepts amp design Addison Wesley 1993 P Booth An introduction to Human Computer Interaction Lawrence Erlbaum 1990 A Dix J Finlay G Abowd R Beale Human Computer Interaction Prentice 1993 L Macaulay Human Computer Interaction for Software Designers Thomson 1995 D Norman S Draper User centered system design Lawrence Erlbaum 1986 J Preece Y Rogers H Sharp D Benyon S Holland T Carey Human Computer Interaction Addison Wesley 1994 B Shneiderman Designing the user interface Addison Wesley 1997 3rd edition About design principles C Brown Human Computer Interface design guidelines Ablex 1989 W Galitz Handbook of screen format design QED 1989 C Gram G Cockton eds Design priniples for interactive software Capman amp Hall 1996 D Hix R Hartson Developing user interfaces Wiley 1993 ISO 9241 Part 10 Dialogue principles Part 12 Presentation of information Part 14 Menu dialogues Part 15 Command dialogues Part 16 Direct manipulat
27. ut e g gestures audio interfaces e g non speech audio tactile and force feedback biophysical signals e g retina scanner M Rauterberg TU e 17 49 Two dimensions for interaction visual feedback FB low high low menu interface MI g i g desktop style interactive directness ID command direct high language manipulation CI DI source Rauterberg 1996 Feel free to have a look at The complete history of HCI M Rauterberg TU e 18 49 What is a Command Language CL CL were used by many early computers and they remain very common e CL may however suffer from un meaningful names CL has usually a prompt e g c gt to tell the user where to type in the commands CL requires commands to expressed using a precise syntax and associated parameters and are intolerant of even the slightest syntactic errors e The initiative of navigation is on the user who has to know what the allowable commands are and to have a clear idea of the function CLis clearly unsatisfactory for novice users but for the expert it typically represents the quickest form of communication especially where abbreviations for commands names are allowed e g lt ctrl gt lt s gt to save a file M Rauterberg TU e 19 49 CL in our daily live e Explanatory Notes to the Merriam Webster Online Dictionary see http www m w com help dictnotes htm e Grammar described at Wikipedia see http e
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