290 likes | 429 Views
CSC 8570 -- USI. Class Meeting 4 September 14, 2010. Topics of the Day. From last time Research project issues Bibliography IRB form Theory and models Good and bad interfaces Lee & Zhai . Extracting design principles Cataloging design principles GOMS review. Where is Gregor ?.
E N D
CSC 8570 -- USI Class Meeting 4 September 14, 2010
Topics of the Day • From last time • Research project issues • Bibliography • IRB form • Theory and models • Good and bad interfaces • Lee & Zhai. Extracting design principles • Cataloging design principles • GOMS review
Where is Gregor? One thousandth of a minute = 6 x one hundredth of a second Diameter of earth = 7926 miles, approximately Claim: Assuming the earth is a perfect sphere, the arc of a circle with central angle of 1/100 second is 1.0+ feet long. (latitude) Claim: At 40 degrees north, the arc of longitudinal circle with central angle of 1/100 second is 0.77+ feet long.
Hand In • Everyone:GOMS model of table creation • Each research team: • Hypotheses, independent and dependent variables • First draft of IRB form • Printout from EndNote of research bibliography
Research Project • Hypotheses (tonight) • Independent variables (tonight) • Dependent variables (tonight) • Bibliography • First entries (tonight) • Continuous process • Background • Formal setting (let’s talk)
Research Project (2) • Short presentation • One spokesperson • Five minutes • Hypothesis, variables, initial experimental design • PowerPoint
Research Project (3) • Experimental design • Between subjects • Within subjects • Sources of bias • Sources of subjects • Logic of conclusions
Lessons from Lee & Zhai • Subjects: 13 total – 9 men, 4 women • Overall design: practice, test, questionnaire/interview • Experiment structure: • Block • Trial
Experimental Design • Within subjects • vs. Across subjects • Randomized order of conditions • Generating random numbers • Balanced Latin square design • Think Sudoku
Experiment 1 • Conditions (10): button type + feedback type • Entry set (5): 1450 X 9276 = ; 8327 – 7231 = ; etc. • Order of entry set randomized • Block (3): Instances of ordered entry set • How many entry set arrangements are possible? • One subject generates 3 x 5 x 10 sets of data • Time, # of corrections
Inferring Design Principles • Augment soft buttons with synthetic feedback • Make soft buttons at least 10 mm wide • Provide automatic error correction for text entry using small buttons
GOMS • Goal • Operators: atomic actions available in the system • Methods: each method is a sequence of operators • Selection Rule:
GOMS Examples • Deleting a message from a mail system folder • Setting a clock or watch • one hour ahead • one hour back • to a particular time • Creating a KWIC index of a list of research paper titles
Clock Setting • Set the clock one hour earlier, the common action at the end of daylight savings time. • GOMS model • Goal: stated above • Operations: • Methods: • Selection Rule:
How Was Your Week? • Write down two examples of system interfaces that were very helpful as you tried to complete a task. • Write down two examples of system interfaces whose design made it difficult for you to complete a task.
Good Interfaces • Who says? • On what basis? • Why were your choices (of helpful interfaces) good? • What were the design principles that promoted “goodness”?
Good Interfaces (2) • iPhone tells when apps to be updated and can be updated all at once: decreases work on part of user, simplicity, allow same operation to be applied to multiple targets in one go (select all) • toolbar shortcuts on a browser (IE): simplifies task, decreases keystrokes, allow accessing “favorites” with simple actions, provide the capability to create shortcuts • purchasing groceries at self-check asks whether cash back w/o drilling down: time-saving (keystroke saving) choices, based on smart choices, combines tasks • using EndNote to add and format references: simplifies (understanding of) task, • Firebug allows manipulating and debugging web page programming • Minipen gives easy translation • Embed a map in a text message • Redbox for renting a DVD • Autocompletion on Garmin GPS
Bad Interfaces • Same questions as for “good” • Who says? • On what basis? • What design principles were violated?
Bad Interfaces (2) • System did not follow standards • ABG antivirus—getting free version (web interface) • Importing songs to iTunes: inconsistent behavior, are there hidden states?, remove all hidden states • Windows XP gives “random” errors • MS messenger • Makefile in C didn’t run – excessive white space: • Moving app from computer to iPod • Selective startup for Microsoft Windows
Good and Bad (2) • What do users want? • Easy to learn • Consistent with what users know already • Quick response time unless perceived as complex • Minimum level of effort to interact • Good information about use • Powerful systems • Accomplishes the task at hand • Compatibility, consistency across systems and platforms • How do designers know? • Do designs match mental models? • What if they don’t?
Good and Bad (3) • Generative User Engineering Principles (GUEPs) • Cognitive Dimensions (CDs) • of notation • of representation in an interface • of understanding NB. In this context a “dimension” is a factor (distinct from others factors)
Next Time • Read Edge and Blackwell, Cognitive Dimensions Tradeoffs in Tangible User Interface Design • You find this paper by going towww.cl.cam.ac.uk/~afb21/CognitiveDimensions • Then choosing the link for the 10th Anniversary Workshop on CDs research • Create a concept map relating the ideas of the paper to one another • Use the concept map software • Make sure you include at least 12 concepts and maybe many more • Consult the papers by Thomas Green for more information • Research project presentation
Modeling Actions • Task analysis: temporal (time) issues • GOMS analysis: method (how to) issues • Keystroke level analysis: operator (widget) issues
Theory Collection Visual processing • Three-stage visual system • Preattentive processing theory (Triesman & Gormican) • Structured object perception theory (Biederman) • Scientific color theory (CIE)
Theory Collection (2) Motor Behavior Models • Hick-Hyman Law: choice time • Keystroke-Level Model: error-free task completion time • Three-state model of graphical input (Buxton) • Fitts’ Law: human movement • Guiard’s Model of Bimanual Skill
Theory Collection (3) Models of Computation • Finite state machine • Grammar in Backus-Naur form (BNF)
Theory Collection (3) Task analysis • Describes the process the user chooses to reach a goal in a specific domain • Hierarchical model using ConcurTaskTrees Design principles • GUEPs • Cognitive Dimensions • Mental models